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MANUAL 


OPERATIVE  TECHNICS 


A   Practical  Treatise  on   the   Elements 
of  Operative   Dentistry. 


By    THOMA.S    B.    WBBKS,    D.    D.    S. 

Professor  of  Operative  Dentistry  and  Dental  Anatomy  in  the  College  of  Dentistry: 
Department  of  Medicine,   University  of  Minnesota. 


PUBLISHED    BY 
,      D.    JUSXI      dt      SOINJ, 

CHICAGO,   ILLINOIS,    U.  S.  A. 

Copyiighted,   1894. 


so 

Hi 


PREFACE. 

It  is  not  my  object  to  present  in  these  pages  an  exhaustive 
work  on  operative  procedure,  or  to  conflict  in  any  way  with  exist- 
ing text-books  on  the  subject,  which,  so  far  as  the  author  is  aware, 
cover  the  whole  ground  over  which  the  student  will  travel  in  his 
three  years'  course  of  study. 

The  suggestions  as  to  what  may  be  done  and  how  the  subject 
may  best  be  presented,  are  the  result  of  the  experience  of  the 
author  and  his  confreres.  Experience  has  shown  that  to  attempt 
to  indicate  to  students  what  and  how  much  they  shall  learn  of 
operative  procedure  from  existing  text-books,  to  enable  them  to  in- 
telligently perform  practical  operations,  involves  an  immense 
amount  of  labor  and  an  expenditure  of  time  which  can  be  better 
employed  in  some  other  direction. 

I  have  attempted  to  present  in  a  compact  form  such  funda- 
mental knowledge  of  operative  dentistry  as  every  student  should 
possess  before  attempting  to  practice  upon  patients,  and  to  direct 
him  how  to  perform  the  various  operations  in  the  technic  labora- 
tory. 

If  we  may  judge  by  the  large  number  of  colleges  which  an- 
nounce technic  courses  in  their  catalogues,  educators  all  over  the 
country  are  alive  to  the  importance  of  a  systematic  course  of 
manual  training  which  shall  give  a  more  thorough  knowledge  of 
the  teeth  and  the  principles  which  underlie  all  operations  upon 
them. 

These  are  the  conditions  prompting  the  attempt  to  outline  a 
course  and  to  present  a  succinct  statement  of  principles,  which 
shall  be  a  primer  on  operative  dentistry  for  the  student,  his  hand- 
book and  constant  reference  while  performing  the  operations  re- 
quired. The  desire  to  be  helpful  to  both  teacher  and  student  has 
been  the  constant  motive,  and  I  hope  that  the  object  may  be  real- 
ized, and  that  the  principles  are  so  represented  that  all  teachers 
may  use  them  as  a  basis  for  their  own  particular  methods. 

T.    E.   W. 


INTRODUCTORY. 

"  New  times  need  a  new  system." 
"To  prevent  going  backward  we  must  work  on  the  line  which  goes  forward." 

In  the  early  history  of  dentistry  the  young  men  who  received 
their  training  from  the  best  practitioners  were,  by  much  practice 
in  the  laborator}',  of  the  purely  mechanical  or  technical,  taught  to 
be  "handy,"  but  with  the  increasing  demand  for  a  more  general 
scientific  knowledge,  there  grew  a  tendency  to  platform  instruc- 
tion— an  extension  of  didactic  work  at  the  expense  of  the  practical. 
In  man}^  instances  this  resulted  in  a  cramming  of  the  head  which 
left  too  little  time  for  training  the  hand. 

There  is  no  escaping  the  truth  of  the  relations  existing  be- 
tween the  mind  and  the  hand.  Some  one  has  called  the  hand  the 
moral  rudder,  the  balance  wheel  of  the  mind.  Certain  it  is  that 
what  the  hand  is  to  execute  is  originated  in  the  mind  j  then 
through  the  eye,  the  mind  directs  the  hand.  Simultaneous  train- 
ing of  the  mind,  the  eye,  and  the  hand  is  the  underlying  principle 
of  the  various  systems  of  manual  training,  to  which  the  teaching  of 
technics  in  dental  colleges  is  analagous. 

Operative  technics  is  generally  understood  to  apply  to  that 
part  of  the  instruction  which  is  obtained  by  operations  upon  teeth 
out  of  the  mouth.  As  this  practice  exercises  the  mind  and  the 
e}  es,  and  increases  the  dexterity  of  the  hand,  it  must  be  allowed 
that  its  governing  principles  are  the  same  as  those  of  manual 
training. 

That  the  dental  student  should  become  "handy"  by  doing 
some  suitable  hand  work,  is  not  only  desirable  but  necessary.  The 
best  teachers  recognize  that  the  child  gains  a  much  better  under- 
standing by  seeing  and  handling  and  doing,  than  by  merely  hear- 
ing and  remembeiing.  They  recognize  also  that  systematic 
training  of  the  hands  is  not  antagonistic  to  mental  growth,  but 
assists  it. 

There  are  two  kinds  of  knowledge — what  we  know  through 
our  own  experience,  and  what  we  know  through  the  experience  of 
others.     What  is /('A/ us  is  another's  •   it  rests  on   a   different  basis 


2  INTR  OD  UCTOR  V. 

from  that  which  we  have  gained  by  our  own  experience.  Does  the 
knowledge  of  the  existence  of  the  ant,  or  the  bee,  or  the  various 
winged  creatures  of  the  woods  make  an  entomologist  or  a  natural- 
ist? Is  a  man  a  machinist  because  he  has  learned  the  parts  of  the 
steam  engine,  and  can  define  axle,  lever,  plane,  and  screv/  ?  Should  a 
man  be  called  a  dentist  because  he  can  name  the  teeth,  bones,  mus- 
cles and  nerves,  describe  the  making  of  amalgams,  or  detail  the  best 
method  of  filling  a  tooth  ?  No,  not  even  if  he  can  rehearse  all  his 
teacher  has  repeated  to  him.  A  purely  mental  acquirement  is  a 
theorem,  and  a  theorem  is  a  demonstrable  proposition.  Whether 
it  may  be  proved  is  always  a  question  until  the  act  of  doing  solves 
the  doubt. 

In  the  progress  of  knowledge,  practice  ever  precedes  theory. 
That  it  is  necessary  for  the  dental  student  to  possess  more  knowl- 
edge than  can  be  gained  from  lectures  and  text-books,  of  the  form, 
structure,  and  diseases  of  the  teeth,  of  the  properties  of  materials, 
and  of  the  forms  and  uses  of  instruments, as  well  as  dexterity  in 
handling  them,  before  he  be  allowed  to  operate  for  patients,  is  now 
generally  acknowledged. 

Prof.  G.  V.  Black,  recognizing  that  the  practical  uses  of  any 
science  or  branch  of  knowledge  are  of  higher  importance  than  the 
purely  intellectual,  sounded  a  distinct  note  for  advance,  in  a  paper 
presented  before  the  Chicago   Odontological  Society  in  June,  1888. 

He  proposed  a  course  in  operative  technics,  which,  without 
limiting  any  part  of  the  instruction  in  operative  dentistry  as  usu- 
ally given,  would  broaden  and  improve  that  teaching,  which  would, 
in  fact,  form  the  basis  iox  didactic  and  clinical  instruction.  He  says: 
"Students  shall  be  taught  the  nature  and  physical  qualities  of  the 
teeth  upon  which  they  are  to  operate,  of  the  materials  they  arc  to 
use,  and  of  the  instruments  by  means  of  which  they  are  to  use 
them.  This  I  would  do  in  a  series  of  object  lessons,  by  having  stu- 
dents handle  teeth  and  study  their  forms  and  examine  enamel  and 
dentine  by  cutting  them  with  instruments;  manipulate  the  material 
used  for  fillings,  study  and  practice  the  use  of  instruments,  and 
learn  the  tests  for  perfect  manipulation."  This  is  the  foundation 
of  the  courses  in  operative  technics  in  the  several  colleges  where 
that  plan  of  teaching  is  in  operation. 

A  course  modeled  on  these  outlines  was  instituted  ia  the  Chi- 
cago College  of  Dental  Surgery  for  the  session  of  1888-9.  The 
Dental   College,   Department    of  Medicine,    of  the    University   of 


INTRO  DUCTORY.  3 

Minnesota  adopted  a  similar  course  the  following  \'car.  Others  fol- 
lowed, until  at  the  present  time  about  one-fourth  of  the  colleges  of 
the  United  States  have  systematic  courses  in  operative  technics. 
Besides  the  outlines  already  referred  to,  and  the  paper  by  Dr.  D. 
M.  Cattell  before  the  World's  Columbian  Dental  Congress,  com- 
paratively little  has  been  written;  nothing  so  far  as  the  writer  is 
aware  which  would  serve  as  a  text  or  reference  book  for  teachers 
and  students  has  been  published.  To  meet  this  demand  is  the 
present  object. 

The  difficulty  of  presenting  any  form  which  in  its  entirety  could 
be  adopted  by  all  teachers,  is  appreciated,  but  an  endeavor  will  be 
made  to  present  a  course  which  shall  embrace  the  principles  which 
underlie  operative  procedure.  It  is  generally  conceded  that  a  fa- 
miliarity with  the  organs  to  be  operated  upon  should  take  prece- 
dence of  all  else;  qonsequently  dental  anatomy  will  be  given  first 
place. 

The  existence  of  so  good  a  text-book  of  dental  anatomy  as 
that  of  Prof.  Black's  removes  the  necessity  of  giving  more  than  a 
few  suggestions  as  to  how  it  should  be  studied  and  the  manner  of 
presenting  the  subject  to  classes.  Experience  has  shown  that 
while  text-books,  models^  charts,  etc,  are  indispensable,  these  are 
not  all  that  is  necessary.  The  teacher  must  study  each  class, 
modify  the  course  to  suit  their  needs,  and  present  it  in  short,  terse 
explanations.  The  introduction  of  these  explanations  at  intervals 
gives  relief  from  the  tedium  of  handling  and  cutting  teeth  and  all 
other  purely  manual  exercises,  as  well  as  carrying  out  the  object 
of  simultaneous  development  of  the  mind,  the  eyes  and  the  hands. 

The  equipment  of  the  technic  laboratory  with  double  curtains, 
a  screen  and  stereopticon,  ready  at  a  moment's  notice  to  present 
images  of  the  teeth  and  their  structure,  has  proved  both  useful 
and  instructive.  These  pictures,  produced  by  photography,  are 
more  accurate,  and  the  method  of  presentation  seems  to  interest 
the  student  and   hold   his  attention  better  than  charts  or  drawings 

do. 

The  syllabus  presented  does  not  include  pathology  or  thera- 
peutics to  any  greater  extent  than  is  necessary  to  elucidate  the 
points  where  they  modify  or  govern  operative  procedure. 

The  object  is  to  fill  the  time  allotted  to  this  work  with  the 
wJiat  and  the  how,  leaving  much  of  the  why  for  subsequent  in- 
struction. 


CHAPTER   I. 


OUTLINE   OF   COURSE. 
OUTLINE    OF    THE    COURSE    BY    DIVISIONS. 


fTerminology  and  nomenclature. 

„         .    ^.         J  Notation. 
Descriptive,    i  r> 

^  I  Form. 


I.     Dental  Anatomy. 


II.     Instruments. 


III.     Canals, 


IV.     Cavities. 


L  Arrangement. 
Macroscopic. 


Structural,      j 

I  Microscopic. 

f  Steel,  its  composition  and  properties. 
J  Shaping,  tempering  and  finishing. 
I  Classification  according  to  form  and  uses. 
lAction  or  use  for  each  form. 

f-Gaining  entrance  to  canals. 
I  Removal  of  pulps. 
"j  Cleansing  and  preparing  canals. 
(^Filling  canals. 

(  Classification  from  location  and  causes. 
I  Preparation  on  principles  governing. 


r 

V.     Pulp  Treatment.      J 

L 


Conservative 


(  Treatment  and  Protection. 


Radical. 


I  Capping. 

S  Surgical  devitalization. 
( Devitalization  by  drugs. 


VI.     Filling  materials. 


f  Characteristics  and  composition. 
I  Preparation. 

]  Introduction  into  cavities. 
l^Finishing  fillings. 

DESCRIPTIVE    ANATOMY. TERMINOLOGY  AND    NOMENCLATURE. 

Recitations  of  first  two  chapters  in  Black's  Dental  Anatomy. 
Each  student  is  furnished  two  brass  rings  about  two  inches  in  di- 
ameter; one  bearing  the  teeth  of  one  side,  superior;  the  other  the 
teeth  on  one  side,  inferior.  Upon  these  teeth  he  will /oca/e  the  dif- 
ferent markings,  as  angle,  apex,  crown,  root,  pit,  sulcus,  groove 
etc. 

Notation. — The  following  notation  is  one  which  furnishes 
the  simplest  form  of  expression  for  any  given  tooth.  It  was 
first  introduced  by  Dr.  Corydon  Palmer.      The  use  of  the  Roman 


G  NOTATION. 

numerals  to  designate  the  deciduous  teeth  was  suggested  by  Dr. 
W.  P.  Dickinson. 

DECIDUOUS  TEETH.  PERMANENT    TEETH. 


V  IV    III    III  III     III     IV  V  8  7  G     5  4     3   2  1  1  3  3  4  5  G  7  8 


V  IV    III    II   I         III     III     IV  V        8  7  6     5  4     3    2  1         12  3  4  5  6  7  8 


Examples, — Right  superior  central  incisor,  permanent,  1  I 
Left  "         first  bicuspid,  "  14 

Right  inferior  second  molar,  deciduous,       V  | 

The  use  of  this  system  saves  much  time  in  labeling  blocks  or 
drawings  and  in  making  records.  It  will  be  used  when  convenient 
in  this  article. 

Form. — Recitation  upon  each  class  of  teeth. 

Selection  of  one  or  more  of  each  class. 

Indicating  upon  these  their  chief  markings. 

Drawing  or  modeling  each  tooth. 

First,  recitation  is  heard  upon  the  superior  incisors.  Follow- 
ing the  recitation,  the  class  make  practical  application  of  the  infor- 
mation gained  from  the  book,  by  selecting  from  a  miscellaneous 
lot  of  teeth,  one  or  more  specimens  of  1  |  1,  and  2  \  2,  pointing  out 
and  naming  their  crowns,  roots,  gingival  line,  surfaces,  angles, 
grooves,  ridges,  and  any  departure  from  the  normal. 

As  it  seems  to  impress  upon  the  student's  mind  the  outline  of 
the  tooth,  the  sections  for  printing  are  cut  while  on  the  study  of 
the  form  of  that  tootli 

Finally,  drawings  should  be  made  of  the  labial,  lingual,  and 
mesial  surfaces  of  1  and  2;  or  what  is  better,  model  each  tooth  in 
clay.      These  last  exercises  must  be  from  memory. 

This  plan  of  study  is  carried  out  upon  all  the  teeth,  deciduous 
and  permanent. 

Arrangement. — All  the  permanent  teeth  are  now  selected  and 
arranged  after  nature,  in  a  dummy  articulator.  (See  Fig.  1.) 
This  exercise  demonstrates  the  students  knowledge  of  arrange- 
ment. 


CV  T  TIXG   SF.  C  T/OA'S. 


Structural  Anatomy. 


Macroscopic. — Cutting  sections,  longitudinal  and   transverse. 

Printing  silhouettes  with  these  sections. 

Studying  form,  location  and  size  of  pulp  chamber  and  canals; 
form  and  thickness  of  enamel,  and  relative  proportion  of  crown  and 
root. 

The  importance  and  advantage  of  this  work  cannot  easily  be 
overestimated.  It  is  the  first  direct  contact  that  the  student  has 
with  teeth.  By  cutting  them  he  is  taught  the  difference  in  the 
character  of  enamel  and  dentine.     It  gives    training  in  the  use  of 


Note. — This  dummy  is  made  by  bolting  two  brass  forms  to  a  strap  hin^e,  which  is 
bent  so  the  joint  comer  above  the  line  of  occlusion.  There  is  a  bolt  passing  through 
it  by  means  of  which  it  may  be  prevented  from  opening  wider  than  two  or  two  and 
one-half  inches,  as  in  Fig.  i  A.  The  forms  have  a  groove  for  the  reception  of  the 
teeth.  In  arranging  tile  teeth  a  thin  layer  of  wax  is  placed  in  the  bottom  of  the  groove, 
which  serves  to  hold  the  teeth  in  position  until  the  proper  arrangnient  is  attained 
when  they  are  finally  invested  in  plaster.  The  teeth  arranged  for  this  exercise  are 
the  ones  upon  which  the  students  perform  the  various  operations  comprised  in  the 
last  four  divisions  of  the  course. 


broaches.  It  fixes  m  his  mind  the  forms  of  the  teeth  and  the  rela- 
tive form,  area,  and  location  of  their  component  parts.  It  teaches 
him  the  system  of  notation,  and,  best  of  all,  it  cultivates  habits  of 
neatness  and  order.  At  the  same  time  it  should  not  be  extended 
until  it  becomes  irksome,  and  it  should  not  trench  upon  time  re- 
quired for  equall}''  important  work.  As  the  result  of  the  author's 
experience,  he   has   introduced    several    modifications  in  the  work 


8  CUTTING    SECTIONS. 

which    he    believes  gives  the  student  the  greatest  benefit  in  the 
shortest  possible  time. 

The  teacher  should  collect,  examine  and  classify  the  teeth  for 
this  work;  he  should  furnish  the  students  with  teeth  and  the  blocks 
for  mounting,  and  he  should  retain  the  sections.  From  this  collec- 
tion, students  of  each  year  will  have  opportunity  to  make  a  much 
better  line  of  prints  than  if  they  were  restricted  to  the  cuttings  of 


Fia.LA 


one  winter.  These  sections  are  filed  in  trays,  holding  six  blocks, 
which  are  incased  in  filing  boxes  holding  twelve  trays. 

Each  student  should  cut  a  section  of  at  least  one  aspect  of 
every  tooth,  and  make  prints  of  every  aspect  of  six  teeth  of  each 
denomination,  in  the  book  provided,  besides  a  duplicate  sheet  of 
each  leaf  for  the  teacher. 

The  teacher  should  cut  on  every  section  the  relief  line  showing 
the  enamel.  This  relief  line  gives  several  advantages:  first,  it 
shows  the  relative  proportion  of  crown  and  root;  second,  it  shows 
the  form  and  thickness  of  enamel  upon  different  parts  of  the  crown 


MARA'/XG  BLOCKS.  9 

and,  third,  it  shows  the  relative  thickness  of  enamel  upon  the  differ- 
ent teeth.  It  is  cut  with  a  minim  wheel  bur,  which  removes  the 
stratum  granulosum.     The  student  needs  for  this  work: 

1  stick  Am.  Ex.  sealing  wax, 

1  half  round  file,  8  inch,  bastard  cut,  medium  coarse, 

1  bench  vise, 

1  alcohol  lamp, 

1  jeweler's  hack  saw,  with  12  saw  blades, 

1  wax  spatula. 

1  excelsior  ink  pad. 

1  rubber  pad  3  in.  x  6  in.  x  ^  in. 

1  book  for  printing,  open  at  end.  Leaves  ruled  as  in  Figs.  6 
and  T. 

Some  fine  canal  explorers,  some  fine  sandpaper,  an  old  tooth- 
brush and  some  cotton  cloth.  To  insure  uniformity,  these  materials 
should  be  selected  by  the  teacher  and  supplied  from  the  clerk's 
desk  at  the  college. 

The  teacher  should  provide  the  teeth  for  cutting,  and  the 
blocks  for  mounting;  also  tablets  of  paper  same  texture,  size  and 
ruling  as  books;  and  some  tablets  of  similar  paper  for  experimental 
printing. 

In  marking  the  blocks  bearing  teeth  which  are  to  be  cut  lon- 
gitudinally, the  abbreviations,  la-labial,  b-buccal,  li-lingual,  m-me- 

1-2-3 
sial  and  d-distal,  may  be  used.     The ^  being  conical, are  usually 

cut  to  the  central  axis.  A  tooth  cut  mesio-distally  would  show  a 
la.  or  li.  aspect,  and  one  cut  labio-  lingually  would  show  a  m.  or  d. 
aspect;  but  to  avoid  confusion  we  will  label  all  sections  cut  in  the 
manner  first  mentioned  la.  and  those  mentioned  second,  m.  If 
transverse  sections  are  printed  upon  pages  ruled  as  in  Fig.  7,  no 
marking  is  necessary  further  than  the  notation. 

The  blocks  bearing  superior  teeth  should  have  figure  denoting 
tooth  in  upper  left  corner,  and  letter  or  abbreviation  denoting  as- 
pect, in  upper  right  corner.     See  Fig.  2. 

Those  for  injerior  teeth  should  have  figure  denoting  tooth  in 
lower  left  corner,  and  letter  or  abbreviation  in  lower  right  cor- 
ner.    See  Fig.  3. 

As  mentioned  before  it  is  an  advantage  to  cut  the  sections  of 
each  tooth  immediately  after  reciting  upon  the  form  of  that  tooth. 
Directions  for  cutting  of  one  will  stand  for  all  of  the  teeth. 


10 


MOUA'TING   AND   FILING. 


Let  each  student  select  from  a  miscellaneous  lot  of  teeth  a 
superior  central,  every  second  student  cuts  la.  aspect,  the  alternates 
cutting  m.  aspect.  Fasten  upon  block  with  sealing  wax,  see  Fig.  4 
and  Fig.  5.  Fix  block  in  vise  ;  holding  the  file  horizontally  at 
an  angle  of  45°  with  long  axis  of  tooth,  cut  rootward  until  pulp 
chamber  is  penetrated.  Pass  a  fine  explorer  through  this  opening 
into  the  canal  and  through  the  apical  foramen;  the  explorer  may 
be  left  in  canal  and  cutting  resumed  until  the  canal  is  exposed  in 
its  entire  length,  when  it  is  removed  and  the  surface  of  section 
made  as  nearly  plane  as  the  direction   of    the  canal   will  permit. 


FIG.2. 


Note. — Blocks  are  i''4^H'^%  inches. 

The  section  will  then  appear  as  in  Fig.  2.  When  the  teacher  has 
accepted  it  and  made  the  relief  line  it  is  ready  for  filing  in  the  col- 
lection. 

All  the  teeth  must  be  mounted  and  cut  as  directed  for  one. 
Better  prints  result  if  the  printing  is  done  after  the  sections  of  a// 
the  teeth  are  cut.  The  printing  is  easy  if  care  is  taken  to  keep 
the  surface  of  sections  clean,  if  too  much  ink  is  not  used,  and  if 
every  part  of  the  surface  is  held  firmly  in  contact  with  the  paper 
long  enough  for  it  to  take  the  ink. 


1893-4. 
Bench  No.  4. 


SILHOUETTES  LONGITUDINAL    SECTIONS. 

FIG.  6. 
GEORGE    HANSOM. 


11 


L  La. 


\  m 


4ftU 


r.  M. 


4.  M. 


WUU 


5.  M. 


nn\ 


6.  B. 


6.  M. 


vv^S'Sff 


Note. — This  page  is  ruled  as  the  pages  in  the  books  are  for  longitudinal  prints.  The  prints 
were  taken  from  sheets  furnished  the  teacher  by  five  students  in  the  Freshmen  class  for  1893-4, 
College  of  Dentistry,  Department  of  Medicine,  University  of  Minnesota. 


13 


TRANSVERSE    SECTIONS. 


In  longitudinal  sections  of 


1-2-3 
1-2-3 


only  la.  and  m.  aspects  need 


4-5-6-7-8  ,      ,.  ,     , 

be    shown,  but    in     ^  ^  ^  ^  ^  b.  li.    m.    and    d.  aspects    should    be 
4-5-6-7-8 

shown.     See  Fig.  6. 

For  transverse  sections  many  teeth  may  be  utilized  which  are 
useless  for  other  work,  as  the  principal  point  to  be  observed  is  at 
or  near  the  gingival  line.  These  sections  cannot  always  be  pre- 
served, but  each  one  of  a  group  of  six  students  may  print  from  the 
other's  cuttings. 

The  value  of  transverse  sections  is  in  showing  the  form  of  root 
canals,  whether  round  or  flattened.  The  pulp  chambers,  located  in 
the  crowns,  are  easily  explored  when  once  penetrated  ;  so  it  is  less 
important  that  their  outlines  as  seen  in  transverse  sections  be 
shown.     Consequently  we  need  not   make   sections,  throughout  its 


FIG.8 


entire  length,  of  more  than  one  tooth  of  each  denomination. 
These  should  be  printed  on  one  page  ruled  as  in  Fig.  7.  Printed 
in  this  manner  they  show  not  only  the  outline  of  pulp  chambers 
and  canals  with  the  outline  of  the  tooth,  but  they  show  the  increase 
in  width  of  interdental  spaces,  from  contact  point  to  gingival  line. 
In  cutting  transverse  sections  the  cuts  between  gingival  line  and 
apex  may  be  made  with  the  saw.  These  sections  may  be  pre- 
served. For  the  supplementary  prints  let  the  students  select 
teeth  whose  crowns  have  been  lost  by  decay ;  six  of  each  denomi- 
nation. Have  them  cut  to  print  view  of  gingival  line,  Fig.  8. 
They  may  then  be  fixed  on  blocks  and  sawed.  Fig.  9.  The  sec- 
tions may  then  be  mounted  on  blocks  and  annotated.  Fig.  10. 


*1_  indicates  that  the  tooth  shown  is  an  upper  central  incisor,  4  indicates  that 
the  view  is  midroot,  and  108  is  the  file  member;  all  of  the  teeth  on  one  page 
have  the  same  file  number. 


SILHOUETTES    TRANSVERSE    SECTIONS. 


13 


F/pT 

(fegr^'e  J/dMo/^,       Fue  no.  109. 


Wd~root  -4. 


Note. — The  prints  on  the  page  were  made  from  transverse  sections  of  all  of  the  teeth  of  the 
left  side.  While  not  taken  from  the  same  mouth  they  were  of  uniform  proportion  and  type. 
Prints  made  in  this  way  are  of  much  greater  value  if  the  teeth  are  so  selected.  Notice  that 
prints  Nos.  3.  4  and  5  are  of  more  importance  than  Nos.  i  and  2. 


14  MICROSCOPIC  ANATOMY. 

STUDYING    FORM,     ETC. 

Recitations  should  be  heard  upon  location  and  form  of  pulp 
chambers  and  canals,  form  and  thickness  of  enamel  and  the 
relative  proportion  of  crown  and  root  as  shown  in  the  prints.  The 
students'  knowledge  should  be  tested  by  requiring  them  to  draw, 
■from  memory,  outlines  showing  these  several  points. 

STRUCTURAL    ANATOMY. 

Microscopic— Kl\xX.Wng  sections  (dry).  Making  drawings. 
Each  student  should  cut  one  longitudinal  and  one  transverse 
section  ;  the  assignment  of  teeth  should  be  such  that  sections  of 
the  several  classes  of  the  teeth  would  be  made  by  the  class  as  a 
whole.  By  studying  the  other's  sections,  each  student  will  receive 
the  same  instruction  upon  all  the  teeth. 

Each  student  should  make  a  drawing  of  that  Which  the  micro- 
scope reveals  of  dentine,  enamel  and  cementum.  If  teeth  are  cut 
and  studied  in  the  regular  course  on  histology  this  part  of  the 
course  may  be  confined  to  study  and  drawings  of  good  photomi- 
crographs thrown  upon  the  screen. 


CHAPTER    II. 


STEEL    AND    INSTRUMENTS. 
STEEL,    ITS    COMPOSITION    AND    PROPERTIES. 

].  If  the  working  of  steel  and  the  manufacture  of  instruments 
is  comprised  in  the  course  in  metallurg}',  instruction  in  the  opera- 
tive technic  laboratory  may  be  confined  to  pointing,  tempering  and 
finishing  of  instruments,  and  the  making  of  canal  explorers  and 
pulp  extractors.  This  practical  work  should  be  supplemented  by 
a  study  of  the  division  on  steel  of  either  Essig's  Metallurgy  or 
Kirk's  Metallurgy  in  the  American  System,  of  Dentistry,  with  a 
didactic  review  and  recitation,  after  the  following  syllabus: 

STEEL. 

Definition,  "an  alloy  of  iron  with  a  small  per  cent  of  carbon." 
(Malleable  iron  also  contains  carbon.) 

Specific  gravity  Y.893  to  7.73(3. 

Melting  point  3272,  F. 

Steel  is  capable  of  being  hardened  and  tempered;   iron  is  not. 

Mild  steel — that  contains  0. 15  or  less  per  cent  of  carbon. 

Hard  steel — that  containing  0.5  to  4  per  cent  of  carbon. 

Mild  steel  is  capable  of  but  little  temper. 

Hard  steel  is  capable  of  much  temper. 

Instrument  steel  contains  about  2  per  cent  of  carbon. 

Steel  is  hardened  to  its  limit  by  heating  to  redness  and  im- 
mediately plunging  in  cold  water.  The  more  carbon  it  contains 
the  harder  and  more  brittle  it  becomes. 

Hardened  steel  maybe  "let  down,"  or  tempered,  by  heating 
to  a  lower  temperature  and  plunging.  Plunging  in  oil  gives  a 
tougher  temper  than  phmging  in   water. 

Steel  may  be  softened  or  annealed  by  heating  to  redness  and 
cooling  slowly;  extreme  softness  is  attained  by  excluding  the  air 
during  the  cooling  process. 

If  overheated,  steel  becomes  blistered,  burnt  and  brittle — in- 
capable of  receiving  a  fine  temper. 


16  WORKING   STEEL. 

Instruments  for  different  uses  require  different  degrees  of 
hardness. 

Color  indicates  the  degree  of  hardness. 

Illustrate  by  holding  a  small  rod  of  poUsJied  hardejied  steel  in 
the  flame  until  the  various  shades,  from  deep  blue  to  faint  yellow, 
appear;  then  plunge.      The  result  will  appear  as  in  Fig.  11. 

For  the  various  dental  instruments  the  temper  as  indicated  by 
color  should  be  as  is  shown  in  table  opposite  Fig.  11. 

PRACTICAL    EXERCISES. 

Filing.  Make  of  piano  wire  several  ver}-  small  and  medium 
canal  explorers,  with  long  taper;  on  a  part  of  these  turn  hooks  for 
pulp  extractors.  To  do  this,  hold  them  in  a  horizontal  position  on 
the  anvil,  covering  one-eighth  of  an  inch  of  the  point  with  the 
large  blade  of  a  penknife,  having  the  edge  of  blade  toward  large 
part,  or  handle,  of  the  explorer.  If  the  blade  is  held  firml}'  against 
the  anvil,  and  the  handle  of  the  explorer  elevated  to  a  perpendicu- 
lar position,  the  point  will  be  turned  at  right  angles  with  the  rest 
of  the  instrument.  It  may  then  be  ground  to  the  proper  length. 
If  desirous  that  the  point  or  hook  be  at  an  acute  angle  with  the 
long  axis  of  the  instrument,  the  instrument  should  be  carried 
further  in  the  turning  process.     The  result  will   be  as  in   Fig.  159. 

Annealing. — Draw  the  temper  in  two  excavator  blanks  by 
lieating  to  redness  and  cooling  slowly.  Draw  the  temper  in  six 
Swiss  broaches  by  laying  on  a  plate  of  iron  and  heating 
to  redness,  allowing  them  to  cool  slowly.  Draw  the  tem- 
per in  six  more  by  laying  them  on  the  iron  and  covering  with 
plaster  Paris  or  pulverized  pumiice,  heating  them  to  redness  and 
allowing  to  cool  before  the  covering  is  removed.  Those  annealed 
by  the  second  process  will  be  softer  and  tougher  than  those 
treated  in  the  manner  first  described. 

Shaping. — From  one  of  the  excavator  blanks  provided,  shape, 
by  cold  hammering  and  filing,  a  small  scaler  same  shape  as 
Figure  78,  length  of  blade  yk  inch,  width  of  each  side  of  blade  at 
base  of  blade  ^^  inch. 

From  another  blank,  by  the  same  process,  shape  a  chisel 
excavator  like  Figure  12,  each  side  or  edge  of  blade  to  be  3^^  inch 
long. 

Polishing.  Remove  all  file  marks  and  polish  with  emery  paper 
of  increasing  fineness. 


CUTTING    INSTRUMENTS.  17 

ffarde/iifig.  Coat  with  soap;  carefully  heat  to  redness  and 
plunge  in  cold  water  slightly  acidulated. — Again  polish. 

Tempering.  To  prevent  too  sudden  a  loss  of  hardness,  place 
point  of  blade  in  contact  with  the  face  of  a  small  hammer.  Hold 
shank  in  the  flame  until  the  proper  colors  appear,  then  plunge 
quickly  in  oil. — Polish. 

Sharpening.  A  keen  edge  should  be  given  on  a  fine  Arkansas 
stone;   be  careful   to  preserve  the  proper  bevel. 

The  above  comprises  the  practical  work,  and  while  not  inter- 
fering with  any  fuller  course  which  maybe  given,  it  enables  the 
student  to  repoint  any  cutting  instrument  and  to  keep  himself  sup- 
plied with  canal  instruments.  It  also  relieves  the  tedium  of  the 
large  amount  of  didactic  work  necessary  in  this  division. 

CUTTING    INSTRUMENTS, 

Dental  instruments  for  cutting  are  analogous  to  such  mechani- 
cal tools  as  the  axe,  chisel,  knife,  saw.,  file,  and  grinding  wheels. 
As  chisels,  excavators,  lancets,  and  scalers  are  similar  in  their  form 
and  action,  they  may  be  considered  together.  Each  of  these  in- 
struments has  three  distinct  parts — the  blade,  the  handle,  and  the 
shank.  The  blade  is  the  acting  part,  that  portion  which  cuts  or 
scrapes.  The  handle  is  that  portion  held  in  the  hand,  b}'  means  of 
which  the  blade  is  manipulated.  The  shank  is  that  portion  which 
connects  the  blade  and  the  handle. 

Blades.  These  are  of  two  forms  ;  one  having  the  bevel  all  on 
one  side.  Fig.  13,  d ;  the  other  having  an  equal  bevel  on  both 
sides,  Fig.  14,  d.  The  advantage  of  the  double  bevel  is  that  both 
sides  cut  equally  well  ;  this  is  not  important  in  instruments  whose 
blades  are  on  a  line  with  the  handle  and  shank.  Fig.  13  ;  but  in 
those  in  which  the  blade  is  beveled  as  in  Fig.  15,  or  in  those  in 
which  the  blade  is  at  an  angle  with  the  axis  of  handle  and  shank, 
as  in  Figs.  14  and  16,  it  may  be  employed  to  obviate  the  necessity 
for  two  instruments.  The  length  of  bevel  or  angle  of  the  cutting 
edge  may  be  ascertained  by  placing  the  edge  of  the  blade  at  the 
center  of  a  circle  which  is  divided  as  in  Fig.  l7.  AVith  one  side 
of  the  blade  upon  the  line  drawn  perpendicularly  through  the  cir- 
cle, the  figure  on  the  periphery  of  the  circle  on  the  line  which  fol- 
lows the  other  side  of  the  blade,  will  indicate  in  degrees  the  angle 
of  the  cutting  edge.  Fig.  IT  «.  Given  the  desired  bevel  or  angle 
of  cutting  edge  for  any  blade,  it  ma}'  be  ascertained  when  it  is  cor- 
rect in  the  manner   just   described.      The  length  of   bevel,  or  thin- 


13 


CLASSIFICATION    OF  INSTRUMENTS. 
CLASSIFICATION    OF    INSTRUMENTS. 


(Blackboard  Diagram.) 


r  Cutting     Instiu- 
ments. 


I    Condensing     In- 
I  struments. 


Instruments. 


Miscell  a  n  e  o  u  s 
Instruments. 


Instruments   for    the 
preparation  of  cav- 
ities and  removal 
of  deposits. 


Instruments  for  finish- 
ing. 


Instruments   for  intro- 
ducing and  condens- 
ing filling  materials. 


Explorers. 

Broaches. 

Clamps. 

Separators. 
Mallets. 


Adjuncts. 


f  Chisels. 
I    Excavators. 
•\    Lancets. 
I    Scalers. 
[  Drills, 

f  Files. 

Saws. 

Trimmers. 

Grinding  instru- 
-;        ments. 

Smootiiing       in- 
I       struments. 
I    Smoothing     ma- 
[       terials. 

Pluggers. 

Burnishers. 

Spatulas. 

Cavity. 
Canal. 

i  Smooth. 
\  Barbed. 
(   Hooked. 

j   Rubber  dam. 
I    Matrix. 

\   Wedge. 
\   Traction. 

(   Hand. 

I   Mechanical. 

l'  Matrices. 

Wedging  mater- 
ials. 

Ligatures. 

Rubber  dam  and 
materials  for 
excluding 
moisture. 

Absorbents. 

Mirrors. 

Pliers. 

Scissors. 

Syringes. 

Check  and 
Tongue  hold- 
ers. 


16  30 


30  BLADES— CHISELS. 

ness  of  edge,  is  governed  by  the  hardness  or  resistance  of  the  sub- 
stance to  be  cut,  and  whether  the  substance  is  to  be  "split"  or 
".shaved."  Enamel  instruments  need  a  stronger  blade  and  shorter 
bevel  than  those  for  cutting  dentine. 

In  chisels  for  direct  cutting,  /.  e.,  where  the  force  may  be 
delivered  direct  from  the  hand  or  mallet  to  the  point  to  be  cut, 
Fig.  19  b,  the  blade  is  on  a  line  with  the  axis  of  the  handle  and 
shank,  and  the  cutting  edge  is  at  right  angles  with  this  axis;  Fig. 
13.  When  the  point  to  be  cut  is  not  accessible  to  direct  force,  i.  e., 
where  the  force  must  be  delivered  from  a  point  represented  by 
Fig.  19  c,  while  the  blade  is  still  on  a  line  with  the  axis  of 
the  handle  and  shank,  the  cutting  edge  may  be  at  an  oblique 
angle,  Fig.  20  ;  or  rounded.  Fig.  21  ;  or  have  three  cutting  edges, 
Figs.  22  and  23.  If  the  cutting  is  to  be  in  a  groove  or  fissure,  the 
blade  maybe  shaped  as  in  Figs.  24,  25,  and  26.  If  the  force  must 
be  dehvered  from  a  point  indicated  by  d,  Fig.  19,  the  blades  must 
be  at  an  angle  with  the  line  of  axis  of  the  handle  and  shank.  Figs. 
2V  to  31.  The  degree  of  angle  may  be  determined  by  placing  the 
central  axis  of  the  shank  upon  the  perpendicular  line  drawn 
through  the  circle,  with  the  center  of  the  angle,  or  junction  of  the 
shank  and  blade  at  the  center  of  the  circle.  The  figure  at  the 
periphery  of  the  circle  on  the  line  which  passes  through  the 
central  axis  of  the  blade  will  show  the  degree  of  the  angle.    Fig  18. 

While  the  blades  of  chisels  and  excavators  do  not  differ  ma- 
terially in  form,  excavator  blades  are  smaller.  They  are  used  in- 
side of  cavities,  and  there  is  always  an  angle  between  the  blade  and 
shank,  or  an  angle  or  curve  in  the  shank.  Angles  and  curves  be- 
tween blades  and  shanks,  and  in  shanks,  are  for  the  purpose  of 
bringing  the  blade  into  direct  action  upon  surfaces  which  are  inac- 
cessible to  straight  instruments. 

Bandies.  These  are  largely  a  matter  of  taste  and  individual 
convenience.  They  should  have  sufficient  length  to  accommodate 
the  hand.  The  handles  of  instruments  designed  for  delicate  work 
and  which  are  held  as  a  pen  is  held,  should  be  small,  while  those 
of  instruments  for  heavier  work  which  are  manipulated  by  a  full 
hand  grasp,  should  be  larger.  Where  a  large  handle  is  desired 
and  weight  is  an  objection,  wood  may  be  used.  Socket  handles 
which  will  carry  any  form  of  point  are  a  great  convenience  to  the 
student.  The  several  styles  in  both  steel  and  wood,  together 
with  the  two  sizes  of  shanks  designed  for  use  with  them,  are 
illustrated  in  Figs.  32-39. 


SNA XA'S—EXCA  VA  TONS— LA XCE  TS.  23 

Shanks.  The  taper  from  handle  to  point  is  for  the  better  bal- 
ancing of  the  instLiiment  as  well  as  giving  lightness  and  delicacy. 
The  angles  and  curves  which  occur  in  shanks,  or  between  them 
and  the  blade,  will  be  shown  in  illustrating  the  more  complex 
forms  of  excavators. 

Excavators.  There  are  three  primary  forms:  the  hatchet,  in 
which  the  width  of  the  blade  is  in  line  with  or  parallel  to  the  axis 
of  handle  and  shank,  Figs.  40-44;  the  hoe,  in  which  the  width  of 
blade  is  at  right  angles  with  the  axis  of  handle  and  shank,  Figs. 
45-49;  thn  spoon  or  scoop,  whose  blade,  in  the  simple  forms,  bears 
the  same  relation  to  the  axis  of  the  handle  and  shank  as  do  the 
blades  of  the  hoe;  the  blades  of  this  form  are  either  round,  pear- 
shaped  or  pointed.  Figs.  50-52.  From  the  great  variety  of  com- 
plex forms  of  curves  and  angles,  only  the  chief  types  will  be  no- 
ticed, showing  first  the  single  instruments.  Figs.  53-Gl.  Those  for 
lateral  cutting,  which  come  in  pairs,  rights  and  lefts,  are  shown  in 
Figs.  62-68.  All  round  pointed  or  convex  edged  instruments  are 
used  where  a  concave  surface  is  desired.  All  square  pointed  in- 
struments are  used  where  angles  are  necessary. 

Lancets  are  designed  for  the  cutting  of  the  soft  tissues,  for  sev- 
ering the  attachment  of  the  gums  at  the  gingival  line,  prior  to  ex- 
tracting; for  making  incisions  for  the  escape  of  pus  in  alveolar  ab- 
cesses,  and  in  all  operations  involving  the  cutting  of  the  soft  tis- 
sues. The  blades  are  of  the  knife  form,  having  a  very  acutety  bev- 
eled, thin  keen  edge.  The  shanks  are  seldom  curved,  and  any 
angles  between  the  shank  and  the  blade  are  governed  by  the  same 
laws  as  those  governing  chisels  and  excavators.  The  tj^pical 
forms  are  illustrated  in  Figs.  eO-Tl.  The  handles,  preferably  of 
ebony,  bone  or  ivory,  are  shown  in  Figs.  TO-Yl. 

Scalers.  These  instruments  are  designed  for  the  removal  of 
hard  deposits  upon  the  teeth.  The  blades  are  similar  to  the  chisel 
and  the  chisel  form  of  excavator.  The  angles  and  curves  of  these 
instruments  are  also  governed  by  the  same  laws  as  those  govern- 
ing chisels  and  excavators.  The  principal  types  are  illustrated  in 
Figs.  72-81.  Those  shown  in  Figs.  72-74  are  designed  to  be  used 
with  a  pushing  motion  in  the  removal  of  deap-seated  calculus  from 
the  roots  of  the  teeth.  Fig.  75  is  for  the  same  purpose,  but  is  used 
with  the  pulling  motion.  Fig,  76  is  also  for  the  same  purpose  and 
can  be  used  both  to  push  and  to  pull.  The  remaining  numbers  are 
for  the  removal  of  the  heavier  deposits  about  the  necks  and  upon 
the  crowns  of  the  teeth;  some  of  these,  notably  Figs.  77  and  78, 
are  useful  in  opening  cavities  and  trinTming  enamel  margins. 


53  64  55  66  57  53  59  60  61 


^=^f=^ 


2'J  DRILLS— FINISHING  BURS. 

Drills.  These  instruments  are  now  seldom  used  except  in  the 
dental  engine.  In  the  technic  laboratory  they  are  used  in  a  revolv- 
ing head  socket  handle.  Fig.  82.  The  Century  Dictionary  gives 
under  the  definition  of  "drills  ' '  not  only  " dental  burs  "  but  all  side 
cutting  instruments  or  "reamers";  under  a  finer  definition  we  may 
consider  drills  as  instruments  for  boring  holes,  and  reamers,  or 
side  cutting  instruments,  as  agents  for  enlarging  openings  already 
existing.  Many  dental  burs  have  the  ability  to  act  both  ways. 
The  instruments  shown  in  Figs.  83-86,  designed  for  working  in 
root  canals,  illustrate  these  three  types.  Fig.  83  is  a  drill,  Figs. 
84  and  85  are  reamers.  Fig  86  is  both  drill  and  reamer.  The 
various  forms  of  drills  are  illustrated  in  Fig.  8*7.  The  several 
forms  of  cavity  burs  are  seen  in  Figs.  88-97.  The  round.  Fig. 
88;  the  oval,  Fig.  89;  the  pear,  Fig.  90;  the  bud.  Fig.  91,  and  the 
pointed  fissure,  Fig.  92,  belonging  to  one  family,  and  cut  the  same, 
i.  e.,  leave  the  same  kind  of  surface,  as  convex  edged,  round  or 
pointed,  spoon  excavators.  The  cone.  Fig.  93;  the  inverted  cone, 
Fig.  94;  the  wheel,  Fig.  95,  and  the  square  or  flat  end  fissure,  Fig. 
96,  are  of  another  family,  and  may  be  used  for  the  same  kind  of 
cutting  as  the  square  end  excavators,  /.  e.,  where  plane  surfaces 
and  angles  are  required. 

INSTRUiMENTS    FOR    FINISHING    FILLINGS. 

Finishing  Burs.  These  are  of  the  same  forms  as  cavity  burs, 
but  are  larger  and  finer  cut.  They  are,  in  fact,  single  cut,  revolv- 
ing files.  There  is  a  newer  form  which  is  double  cut,  made  in  two 
forms,  round  and  pear-shaped. 

Files.  The  file  is  a  tool  too  well  known  to  need  special 
description.  The  introduction  of  the  dental  engine,  with  its 
diverse  armament  of  burs,  has  almost  entirely  abolished  the  use 
of  files  except  for  the  finishing  of  fillings.  The  separating  file  is 
still  useful  in  some  fo.rms  of  cavity  preparation.  The  so-called 
"flexo  files"  are  the  favorites,  being  sufficiently  soft  to  bend  with- 
out breaking.      The  "flexo"  separating  file  is  shown  in  Fig.  98. 

The  chief  use  of  the  finishing  file  is  at  clie  cervical  margin  of 
fillings  on  the  proximate  surfaces.  Those  known  as  file  trimmers 
are  made  with  handles  similar  to  those  of  excavators  and  scalers. 
Fig.  99.  Those  known  as  files  have  handles  like  the  "  flexo"  fin- 
ishing file  shown  in  Fig.  100,  or  like  the  one  shown  in  Fig.  101. 
Many  are  made  double  end,  Fig.  102.  Of  the  many  forms  only  a 
few  of  the  most  useful  will  be  illustrated.  Fig.  103. 


M 


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85  86 


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89 


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91  92  93 


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Li 


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95  96 


101 


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103 


.V.J  JVS—  TRIMMERS— DISKS.  29 

Saws.  These  are  used  in  separating  and  in  trimming  the 
cervical  margins  of  fillings.  They  are  generally  used  in  a  frame, 
Fig.  104,  and  are  made  with  teeth  on  one  edge,  Fig.  104  «;,  or 
with  teeth  on  both  edges,  Fig.  104  b.  Flexo  files  are  also  made 
for  the  saw  frame. 

Trhnmers.  These  instruments  are  decigned  for  shaving  or 
paring  the  surfaces  of  proximate  fillings.  They  have  very  thin 
lancet-like  or  chisel-like  blades.  The  chief  forms  are  seen  in  Fig. 
105.  The  sickle  scalers.  Fig.  '11,  if  sharpened,  make  very  effective 
trimmers. 

Grinding  Instruments.  These  are  in  the  form  of  wheels,  disks 
and  points.  Wheels  are  simply  small  grindstones,  of  varying 
thickness,  varying  in  diameter  from  one-fourth  of  an  inch  to  an 
inch.  The  great  variety  of  disks  and  points  are  shown  in  Figs. 
106  and  107.  They  are  made  of  corrundurc,  Arkansas,  Scotch  and 
Hindostan  stones,  and  of  copper  charged  with  diamond  dust. 

Corrundum  is  the  native  crystalline  oxide  of  aluminum;  in 
hardness  it  ranks  next  to  the  diamond.  The  purest  forms  of  cor- 
rundum are  the  gems,  sapphire,  Oriental  amethyst,  ruby,  and 
Oriental  topaz.  It  is  the  darker,  opaque  varieties  which  are  pul- 
verized for  grinding  purposes.  In  the  ordinary  corrundum  disks 
and  points  it  is  combined  with  shellac,  while  in  the  hard  rubber 
and  corrundum  combination  it  is  incorporated  into  the  rubber 
before  vulcanizing.  A  newer  form  is  "carborundum,"  which, 
being  vitrified,  cuts  well  and  wears  slowly. 

Disks  and  points  of  Arkansas,  Scotch  and  Hindostan  stones 
are  used  in  the  finer  grinding  for  finishing  enamel  margins  and 
fillings.  The  copper  and  diamond  disks  and  points  are  used  in 
separating,  cutting  enamel,  and  finishing  fillings.  Disks  are  made 
of  emery,  sand,  garnet,  and  cuttle  fish  paper.  All  but  the  cuttle 
fish,  which  is  very  fine,  grade  from  coarse  to  fine.  Disks  of 
these  materials  are  of  three  forms:  plain,  depressed,  and  safe 
center,  Fig,  108.  The  last  two  are  in  three  sizes  only,  while  the 
plain  ones  range  from  three-sixteenths  of  an  inch  to  an  inch  in 
diameter.  Cloth  and  paper  strips  of  the  same  grits  as  those  on 
paper  disks,  are  used  for  finishing  the  proximate  surfaces  of  fillings. 
Short  pieces  of  these  strips  are  used  in  a  pcrte  for  the  engine  for 
polishing  other  surfaces.  Fig.  109.  Disks  for  carrying  such 
polishing  powders  as  pumice,  silex,  chalk,  oxide  of  tin,  and  rouge 
are  made  of  celluloid,  felt,  and  soft  rubber.  Points  for  the  same 
purposes  arc  made  of  wood,  leather,  felt,  and  soft  rubber.  These 
are  useful  in  polishing  teeth  and  fillings.  Instruments  for  carrying 
disks  and  points  are  illustrated  in  Fig.  lO^io. 


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108 


109 


109Js 


SPA  TULA  S—PL  UGGERS.  31 

INSTRUMENTS      FOR      INTRODUCING      AND      CONDENSING      FILLING 

MATERIALS. 

Spatulas.  Tiiese  are  defined  as  instruments  "having  broad, 
flat  blades  with  unsharpened  edges,  r3ed  for  spreading,  smoothing, 
scraping  up,  or  stirring  substances."  In  operative  procedure  they 
are  used  for  mixing  cements,  introducing  the  mass  into  the  cavit}', 
and  smoothing  the  filling.  With  the  addition  of  a  round  point,  a 
ball  end  point,  and  a  lancet  trimmer,  cements  may  be  manipulated 
entirely  with  spatulas,  or  spatula-like  instruments.  The  different 
forms  are  illustrated  in  Figs.  110-113.  The  ball  end  and  the 
round  points  are  shown  in  Figs.  114  and  115.  Some  forms  of 
noncorrosive  instruments,  made  of  platinum,  are  seen  in  Figs. 
115-117. 

Phtggers.  This  is  the  name  given  to  instruments  for  the  con- 
densation of  gold  and  other  filling  materials.  Condensing  instru- 
ments are  for  the  purpose  of  conveying  force  or  impact  from  the 
hand  or  mallet  to  points  inaccessible  to  the  hand  or  mallat.  The 
solidity,  homogeneity,  or  density  of  fillings  is  attained  in  one  of 
three  ways.  By  introducing  the  material  in  a  plastic  condition 
and  allowing  it  to  harden  ;  by  wedging  or  interweaving  folds  or 
rolls,  made  from  very  thin  sheets  of  metal  ;  or  by  welding  small 
pieces  of  metal  together  in  the  cavity.  Each  of  these  methods 
requires  instruments  peculiar  to  itself. 

Instruments  described  for  the  introduction  of  cements  with  the 
addition  of  the  serrated  points.  Figs.  118  and  119,  comprise  the 
necessary  forms  for  the  introduction  of  amalgam,  gutta-percha 
and  zinc  plastics. 

Tin  and  noncohesive  gold  are  introduced  by  wedging  or  inter- 
digitation  ;  instruments  must  have  wedge-shaped  points,  and  all 
serrations  must  be  sharp  and  deep.  In  Figs.  120-129,  are  shown 
the  several  forms  of  points,  also  the  angles  and  curves  in  the 
shanks  which  are  necessary  to  bring  the  points  into  direct  action 
upon  all  surfaces.  These  instruments  are  used  chiefl}'  b}'  hand 
pressure. 

Cohesive  gold  is  introduced  in  small  pieces,  welded,  or  fast- 
ened together  in  the  cavity.  To  accomplish  this,  the  points  of  in- 
struments must  have  "faces,"  which  will  bring  the  surfaces  of  the 
gold  into  perfect  contact.  These  faces  are  either  flat  or  convex,  with 
fine,  shallow  serrations.  Pluggers  used  with  the  mallet  have 
handles  like  Fig.  130.  The  faces  have  various  outlines,  circular 
oval,  square,  oblong,  pear-shaped  and  triangular.      The  points  are 


n 


110 


111 


113 


113 


114 


118       119 


CD 


147 


148 


149        150 


151      153 


PLUGGER  POINTS.  33 

plain,  as  illustrated  in  Figs.  130-132,  or  foot-shaped,  as  m  Figs. 
133-138.  The  shanks  of  pluggers  have  various  styles  of  curves, 
the  single  curve,  Fig.  132,  the  bayonet,  Fig.  12V,  and  the  cork- 
screw, Fig.  129. 

Curves  in  the  shanks  of  pluggers  are  for  the  same  purpose  as 
in  other  instruments,  /.  e.,  to  bring  the  point  into  direct  action 
upon  surfaces  inaccessible  to  straight  instruments.  Angles  in 
shanks  do  not  divert  the  force.  If  a  plate  of  steel,  shaped  like  Fig. 
139,  is  struck  with  a  hammer  at  A,  or  at  any  point  on  the  end 
between  A  and  B,  the  force  will  be  delivered  from  C,  in  the  direc- 
tion indicated  by  the  arrow,  /.  <?.,  on  a  line  parallel  with  the  long 
axis  of  the  figure.  If  portions  of  the  plate,  E  and  F,  are  cut  away, 
leaving  D,  D,  D,  the  result  of  a  blow  at  A,  will  be  the  same  as 
before,  provided  there  is  no  spring  in  the  angles.  The  law  of 
force,  as  applied  to  pluggers,  is,  that  whatever  the  curve  or  angle 
in  the  shank,  the  force  is  delivered  on  a  line  parallel  with  the  long 
axis  of  the  instrument,  provided  that  the  face  of  the  point  is  at 
right  angles  to  this  axis.  Force  is  delivered  at  right  angles  with 
the  face  of  the  instrument.  If  two  perfect  spheres,  A,  are  placed 
upon  a  smooth  plane  surface.  Fig.  140,  and  struck  simultaneously 
with  the  end  of  an  oblong  figure,  B,  they  will  roll  along  the  dotted 
lines  c  c.  The  same  spheres  struck  with  a  wedge-shaped  figure. 
Fig.  141,  will  travel  along  the  lines  c  c,  i.  e.,  at  right  angles  to  the 
surface  that  struck  them.  If  the  spheres  are  struck  with  a  disc,  B., 
Fig.  142,  they  will  travel  along  the  lines  c  c  dit  right  angles  to  the 
surface  at  the  point  of  contact.* 

From  these  illustrations  the  conclusion  will  be  readily  drawn 
that  when  spreading  of  the  filling  material  is  desired,  a  convex  sur- 
face is  preferable  to  a  flat  one.  In  Fig.  143,  is  shown  a  ball  end 
plugger  with  serrations  running  over  on  the  side  ;  a  sectional  out- 
line is  represented  by  B,  Fig.  142.  This  instrument  is  not  only 
effective  in  spreading  the  gold,  but  its  spherical  form  enables  the 
operator  to  deliver  the  force  in  any  direction  he  desires  simply  by 
bringing  different  points  of  the  face  in  contact  with  the  surface  of 
the  filling. 

In  Figs.  144-146  are  shown  three  bayonet  pluggers  with  tri- 
angular foot  points,  having  convex  faces,  serrated  longitudinall}'' 
only.  They  are  designed  for  matrix  fillings  in  disto-occlusal  sur- 
faces of  bicuspids  and  molars,  the  pointed  foot  making  it  easy  to 

*  NOTE. — The  author  is  under  obligations  to  Dr.  E.  A.  Royce  for  the  suggestion  of  the  ilhis- 
trations  of  force,  as  shown  in  Figs.  139-142.  Dr.  Royce  is  also  the  designer  of  the  ball  v-;iid 
pluggers  illustrated  by  Fig.  143. 


■ 

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lao 


143         144  145  14G 


MISCELLANEOUS  INSTRUMENTS.  35  ' 

carry  the  gold  well  into  the  joint  between  the  matrix  and   the  mar- 
gin of  the  cavity. 

Burnishers.  These  instruments,  made  of  steel,  agate  and 
bloodstone,  are  used  in  spreading  and  smoothing  metalhc  fillings, 
also  in  the  insertion  and  adaptation  of  cement,  gutta-percha,  and 
amalgam.  The  various  forms  are  shown  in  Figs.  14'7-152.  Bur- 
nishers are  hand  instruments,  but  they  are  also  made  for  use  in  the 
engine. 

MISCELLANEOUS    INSTRUMENTS. 

Explorers.  Cavity  explorers  are  for  searching  out  cavities  in 
the  teeth,  and  should  be  of  a  spring  temper  with  very  delicate 
points.  The  most  useful  forms  are  shown  in  Fig.  153.  Canal  ex- 
plorers are  delicate,  pointed  instruments  with  a  long  taper.  An 
exceedingl}'  delicate  form  called  a  bristle,  mounted  in  an  ebony  or 
rubber  handle,  is  very  useful  in  following  intricate  canals,  Fig.  154. 

Broaches.  The  instruments  described  as  canal  explorers  aie 
also  known  as  smooth  broaches.  Another  form,  Swiss  broaches, 
are  square,  and  hard  tempered.  When  the  temper  is  drawn  they 
are  useful  in  carrying  medicaments  and  wiping  canals;  their 
square  form  making  it  easy  to  cover  them  with  cotton. 

Barbed  broaches  are  those  which  have  a  row  of  barbs  on  one 
side.  Fig.  156,  and  one  of  a  different  style  of  barbs  in  Fig.  15Y. 
Hooked  extractors  have  been  noticed  in  the  practical  work;  Fig.  158 
showing  the  form  of  the  ones  manufactured  by  the  students,  while 
Fig.  159  shows  another  form.  All  small  canal  instruments  are  more 
easily  manipulated  if  they  are  inserted  in  small  handles  like  Fig. 
154,  or  in  broach  holders.  Figs.  160  and  161. 

Clamps.  Rubber  dam  clamps  are  designed  to  hold  the  rubber 
dam  in  position  on  teeth  where  simple  ligatures  will  not  retain  it. 
They  are  made  of  thin  spring  steel,  in  man}^  forms,  and  are  applied 
by  means  of  forceps  designed  for  that  purpose.  Figs.  162-165 
show  four  clamps  which  are  a  very  satisfactory  selection  for 
students.  Figs.  162  and  163  are  molar  dip  clamps,  right  and  left; 
the  dip  flange  carries  the  rubber  below  the  cervical  margin  of 
buccal  cavities.  Figs.  164  and  165  are  irregularity  clamps,  right 
and  left,  and  are  to  be  used  on  bicuspids  or  third  molars. 

Matrix  Clamps.  These  are  for  the  purpose  of  holding  a  thin 
strip  of  metal  in  position  around  a  tooth  having  a  mesio-occlusal  or 
a  disto-occlusal  cavity,  for  the  purpose  of  converting  it  into  a  sim- 
ple cavity  and  shaping  the  proximate  surface  of  the  filling.  They 
are  of  two  forms,  the  spring  and  the  screw  clamp.  Fig.  166  illus- 
trates the  spring  and  Figs.  16V  and  168  show  the  screw. 


Fia.  139. 


»- 


B 


Fig.  140. 


E 


Fig.  142. 

V  c 


CLAMPS   AND    SEPARATORS.  37 

Separators.  The  general  rule  is  that  in  proximate  cavities, 
space  for  filling  should  be  gamed  by  cutting,  and  space  for  finish- 
ing should  be  gained  by  wedging,  separating  sufficientl}^  to  per- 
mit the  manipulation  of  disks  or  strips.  The  simplest  way  to 
accomplish  this  is  with  a  wooden  wedge,  or  a  block  of  wood,  in- 
serted to  hold  the  space  which  has  been  gained  by  forcing  between 
the  teeth  to  be  separated,  an  instrument  like  Fig.  1G9,  but  the 
operation  may  be  performed  with  less  pain  by  the  use  of  one  of  the 
screAV  separators.  These  are  of  three  kinds;  those  which  wedge  or 
force  the  teeth  apart  by  the  approach  of  two  points,  Fig.  IVO;  those 
which  draw  the  teeth  apart  by  the  separation  of  two  pairs  of  points, 
Fig.  iVl,  and  those  which  act  in  both  ways,  Fig.  172. 

Mallets.  Hand  mallets  are  made  of  wood,  steel,  lead,  and 
many  other  materials.  The  handles  are  long  or  short,  round  or 
fiat,  as  the  operator  may  fancy.  The  author,  however,  has  found 
most  satisfactory  to  both  operator  and  patient,  a  mallet  of  lead  in 
a  brass  case,  having  the  ends  covered  with  leather,  and  a  handle 
similar  to  those  in  riveting  hammers,  Fig.  173. 

Mechanical  mallets  are  of  four  kinds:  the  pneumatic,  in  which 
the  blow  is  delivered  to  the  end  of  the  plugger  by  a  loaded  piston 
projected  by  the  sudden  pressure  of  air;  the  electro-magnetic,  in 
which  the  end  of  the  plugger  is  struck  by  a  hammer  operated  by 
the  opening  and  closing  of  an  electric  circuit;  the  mechanical,  in 
which  the  blow  is  delivered  by  a  rapidly  revolving  disk  having  a 
hardened  steel  projection  let  into  its  rim;  the  automatic,  in  which 
the  blow  is  delivered  by  releasing  a  spring.  The  last  form  is 
now  made  double  end,  to  operate  either  a  direct  or  a  return  plug- 
ger. Fig.  174.  The  one  which  delivers  a  blov/  most  resembling 
that  of  the  hand  mallet  is  the   pneumatic. 

ADJUNCTS. 

Matrices.  These  appliances  are  of  various  forms  from  the  sim- 
ple slip  of  polished  metal,  held  in  position  against  the  margins  of 
the  cavit}'  by  a  wedge,  to  the  continuous  band  with  its  several 
methods  of  adaptation.  Matrices  are  of  three  forms;  those  occu- 
pying but  one  interdental  space,  depending  upon  the  presence  of 
an  adjoining  tooth  for  their  retention,  Figs.  175-177;  those  occupy- 
ing but  one  interdental  space,  not  dependent  upon  an  adjoining 
tooth  for  retention,  which  partially  encircle  the  tooth  and  are  re- 
tained by  the  spring  or  screw  clamp,  as  shown  in  Figs.  1G6  and  167, 
and  those  which  occupy  two  interdental   spaces,  that  are  tightened 


154 


160  161 


173 


174 


MATRICES.  39 

about  the  tooth  by  the  various  devices  shown  in  Figs.  178-180  and 
in  Fig.  168.  The  sHps  or  bands  of  metal  forming  the  matrix  are  of 
varying  composition,  form  and  thickness.  The  general  rules  are, 
that  the  material  should  be  either  steel  or  German  silver,  highly 
polished,  thin  enough  to  be  readily  adapted,  not  occupy  too  much 
space,  and  of  such  shape  as  to  insure  perfect  adaptation,  and  give 
to  the  completed  filling  the  desired  contour. 

Wedgifig  materials.  For  slow  wedging  in  those  cases  where 
space  lor  operating  must  be  gained,  some  material  which  is  capable 
of  expansion  should  be  inserted,  increasing  its  bulk  from  time  to 
time,  until  the  space  is  sufficient.  The  materials  employed  are 
dry  wood,  cotton,  and  rubber. 

RUBBER    DAM    AND    MATERIALS    FOR    EXCLUDING    MOISTURE. 

For  short  operations  teeth  may  be  isolated  and  protected  from 
the  saliva,  by  surrounding  them  with  small  napkins  properly 
folded  or  rolled,  cotton  rolls,  or  some  of  the  paper  or  cottonoid 
preparations.  For  more  protracted  operations  rubber  cloth  of 
medium  thickness  should  be  used.  In  its  application,  the  teeth  to 
be  isolated  are  passed  through  round  holes,  formed  with  a  punch, 
and  the  edges  of  the  rubber  encircling  the  teeth  turned  rootward. 
If  the  teeth  are  conical  or  if  the  tissues  exert  a  contra  pressure  the 
rubber  is  held  in  place  by  ligatures  or  by  the  steel  clamps. 

Ligatures.  That  the  gums  may  be  injured  as  little  as  possible, 
and  that  the  ligature  shall  not  be  in  the  way,  the  ordinary  knitting 
silk  is  used  for  the  retention  of  the  rubber  dam.  Floss  silk,  hemp 
thread  known  as  '^  gilling  twine,"  and  small  sea  grass  fish  line  are 
sometimes  used;  the  last  being  very  efficient  where  much  strength 
is  necessary,  as  in  regulating. 

Absorbeiits.  Cotton  prepared  in  such  a  manner  as  to  absorb 
moisture  readily,  spunk,  and  a  thin  absorbent  paper  known  as  "bi- 
bulous paper,"  are  the  chief  agents  used  for  wiping  and  drying 
the  surfaces  of  the  teeth,  and  cavities. 

Mirrors.  Mouth  mirrors  are  used  for  reflecting  the  light  into 
cavities  and  for  showing  cavities  upon  such  surfaces  as  are  out  of  di- 
rect line  of  vision.  Those  which  magnify  concentrate  the  light  and 
enlarge  the  reflected  image,  so  that  by  their  use  operations  are  per- 
formed with  less  eye  strain. 

Pliers.  Instruments  known  as  foil  carriers  and  dressing  pliers 
are  the  only  form  of  pliers  which  will  be  noticed  here.  They  are 
not  onl}^  for    conveying  gold   to  cavities  but  for  all  small  objects 


PLIERS.  11 

which  are  handled  in  operating,  and  carrying  cotton  charged  with 
various  medicaments.  For  this  last  purpose  one  pair  made  of  non- 
corrosive  metal  should  be  provided. 

The  various  other  adjuncts  in  the  operative  armamentarium 
will  not  be  noticed  in  this  course  except  as  they  appear  in  some  of 
the  procedures  treated  in  other  divisions. 


CHAPTER   III. 


CANAL   TREATMENT. 
(Blackboard  Diagram.) 


Opening   into   Canals. 


Canals      with      recently      devitalized 
pulps. 


r 


Canals  containing  putrescent  pulps.  J 


Apply  rubber  dam. 

Open    cavity  or    penetrate  crown    to 

pulp  chamber. 
Remove  decay. 
Enlarge  point    of   penetration    to  the 

diameter  of   the  pulp  chamber. 

Remove  pulp. 
Enlarge  canals. 
Dry  thoroughly. 
Fill  canals. 

Render  inert  the  contents  of   canals. 
Remove  contents  of  canals. 
Ream  if  necessary. 
Render  aseptic. 
Dry. 

Fill,    if    there    are   no   pericemental 
complications. 


Having  learned  the  forms  oi  instruments,  a  knowledge  of  their 
use  follows  sequentially.  Gaining  entrance  to  canals  and  cleansing 
them,  brings  into  use  chisels,  excavators,  drills,  burs,  reamers,  ex- 
plorers and  broaches;  chisels  to  break  down  enamel,  excavators  to 
remove  decayed  dentine,  drills,  burs  and  reamers  to  make  and  en- 
large openings  into  pulp  chambers,  explorers  to  follow,  and 
broaches  to  cleanse  canals. 

Before  proceeding,  instruction  should  be  given  on  the  rubber 
dam,  and  the  students  exercised  in  its  application;  first  without 
ligatures  or  clamps,  then  with  their  assistance.  The  following  rules 
should  be  inculcated  as  the  basis  of  instruction  in  the  use  of  the 
rubber  dam. 

When  the  cavity  has  been  rendered  aseptic  in  teeth  having 
living  pulps,  the  fluids  of  the  mouth  should  not  again  be  allowed 
to  enter. 

In  pulpless  teeth,  when  a  pulp  chamber  has  been  penetrated 
for  treatment,  the  fluids  of  the  mouth  should  not  again  be  allowed 
to  enter. 


44  APPLYING    THE   RUBBER   DAM. 

Sufficient  space  should  be  left  between  the  holes  to  allow  the 
rubber  to  easily  cover  the  festoon  of  gum  between  the  teeth  so 
that  this  point  of  gum  tissue  will  not  be  strangulated  in  one  or  the 
other  of  the  holes. 

Ligatures  or  clamps  should  not  be  used  unless  absolutely 
necessary,  and  ligatures  should  be  as  small  as  possible. 

Rubber  dam  should  never  be  applied  until  it  has  been 
thoroughly  sterilized.     This  is  best  accomplished  by  boiling. 

PRACTICAL    EXERCISES. 

1.  Applying  the  rubber  without  ligatures  to  two  or  more  teeth. 

2.  Ligating,  using  the  several  forms  of  knot. 

3.  Applying  the  rubber  on  molar  tooth  and  adjusting  the 
clamp. 

4.  Carrying  the  rubber  to  position  on  molar  tooth  with  the 
clamp. 

5.  Appl3-ing  rubber  to  incisor  or  cuspid  having  labial  cavity 
near  gingival  line,  carrying  it  below  cervical  margin  of  the  cavity 
and  retaining  it  with  copper  wire. 

6.  Applying  rubber  on  molar  tooth  and  ligating  glass  beads 
in  position  for  its  retention.* 

CANALS. 

Gaining  Entrance  to  Canals.  If  there  is  no  cavity,  or  if  exist- 
ing cavities  have  fillings  which  it  is  not  desirable  to  remove, 
entrance  should  be  made  at  the  point  which  will  give  the  most 
direct  access  to  pulp  chamber,  and  leave  the  greatest  strength  to 
the  tooth.  The  point  where  the  drill  should  be  inserted  in  each 
tooth  is  indicated  in  Fig.  181.  If  there  be  more  than  one  canal 
the  drill  should  be  held  as  nearly  as  possible  in  line  with  the 
principal  one.  The  initial  opening  made  by  the  drill  should  be 
sufficiently  enlarged  with  burs  or  reamers,  to  permit  of  perfect 
access  to  every  part  of  the  pulp  chamber,  and  to  all  canals. 

If  there  is  a  cavity  in  the  tooth,  entrance  to  the  canals  should 
be  made  through  it.  The  first  step  should  be  the  free  opening  of 
the  cavity  and  the  removal  of  all  decay  \  the  next,  the  opening  into 
the  pulp  chamber  or  the  enlarging  of  existing  openings  until  the 
walls  of  the  pulp  cavity,  the  pulp  chamber  and  the  canals  are  con- 
tinuous. The  openings  into  canals  should  be  as  nearly  funnel 
shaped  as  conditions    will  permit.     Fig.   182    shows  the  form  for 

*The  various  operations  in  all  practical  exercises  should  first  be  performed 
by  the  teacher  in  the  presence  of  the  class. 


PENETRATING   PULP   CHAMBERS. 


45 


each  tooth  ;  the  labial  and  buccal  views  give  the  torm  where 
entrance  is  gained  through  a  cavity,  and  the  mesial  aspects  illus- 
trate the  enlarged  openings  made  b}^  the   drill. 

PRACTICAL    WORK. 

When  the  teeth  are  selected  for  the  exercise  in  arrangement 
care  should  be  taken  that  each  articulator  contains  a  tooth  of  each 


class,  having  a  cavity  in  which  the  pulp  is  penetrated.  The 
student  should  now  be  directed  to  perform  his  practical  canal 
work  upon  these  teeth. 

For  the   initial  exercises  in  the  use  of   chisels  and  excavators 
the  badly  deca3'ed  teeth  which  are  useless  for  filling  or  for  sections 


4G 


OPENING   CAVITIES. 


may  be  utilized  to  good  advantage  for  practice  in  enamel  cleavage 
and  the  cutting  of  dentine,  before  the  student  uses  these  instru- 
ments upon  the  teeth  mounted  in  the  articulator. 

Opening  the  Cavity.     The  enamel  should  be  cut  away  until  the 
cavity  is  freely  opened,  as  in  Fig.  183.      This  should  be  done  with 


Vi 


enamel  chisels,  Figs.  12,  13  and  29.  The  two  ways  of  holding  the 
chisels  are  illustrated  in  Figs.  184  and  185.  For  this  first  exercise 
the  student  need  not  confine  himself  to  the  positions  necessary 
when  operating  for  patients,  but  he  may  approach  the  cavity  from 
any  point  which  affords  the  most  direct  access. 


OPENING  PULP    CHAMBERS. 


47 


Removal  of  Decayed  Dentine.  All  disorganized  dentine  should 
be  scooped  out.  For  this  purpose  spoon  excavators  are  used,  the 
strokes  being  made  from  the  center  toward  the  periphery.  This 
exercise  gives  training  in  the  use  of  the  direct  spoon,  Figs.  50  to 
52,  and  the  rights  and  lefts,  Figs.  65-68.  The  cutting  should  be 
continued  until  the  point  of  entrance  to  pulp  chambers  is  fully- 
exposed. 

Enlarging  the  Opening.  If  the  cutting  or  reaming  is  done  with 
a  bud  shaped  bur,  Fig.  91,  manipulated  by  means  of  the  revolving 
head  bur  holder,  Fig.  82,  this  step  gives  some  familiarity  with  the 


183 

use  of  burs.  The  opening  should  be  enlarged  to  the  diameter  of 
the  pulp  chamber,  if  possible.  Up  to  this  point  the  procedure  is 
the  same  for  both  recently  devitalized  or  putrescent  pulps. 

CANALS    WITH    RECENTLY    DEVITALIZED    PULPS. 

Removal  of  the  Pulp.  This  may  be  accomplished  with  the 
barbed  broaches,  Fig.  155  or  157  ;  with  the  hooked  extractors.  Fig. 
158  or  159;  or  with  the  Swiss  broaches  which  have  first  been 
wrapped  with  a  shred  of  cotton. 

Enlarging  Canals.  If  canals  are  enlarged  at  all  they  should 
be  reamed,  not  drilled.  The  only  safe  instruments  are  those  shown 
in  Fig.  84  or  86  ;  the  latter  have  a  safe  or  guiding  point.  The 
advantages  of  reaming  are  that  it  insures  the  thorough  removal  of 


48 


ENLARGING   AND   DRYING    CANALS 


all  pulp  tissue  and  renders  less  difficult  the  insertion  of  the  filling 
material.  Attention  is  called  to  the  shape  of  the  various  canals  as 
shown  in  the  silhouettes  of  both  longitudinal  and  transverse  sec- 
tions, and  emphasis  is  given  to  the  fact  that  all  attempts  at  enlarg- 
ing flattened  07-  torti(07is  catials  are  attended  with  the  datiger  of  perfo- 
rating the  side  of  tlie  root.  Hence  we  draw  the  conclusion  that  the 
canals  which  it  is  safe  to  enlarge  are  those  which  are  round  and 
straight.  When  there  is  necessity  for  enlarging  canals  which  are 
departures  from  this  form,  the  greatest  care  should  be  exercised. 
Drying  Canals.     In   cases  of   recent   devitalization,    after  the 


1S4 

removal  of  the  pulp  and  the  enlargement  of  the  canals,  if  the 
saliva  has  been  excluded  there  is  an  aseptic  condition,  and  the 
canals  are  read}^  for  filling.  Before  its  introduction,  the  canals 
should  be  thoroughly  dried.  Wiping  them  with  absorbent  paper 
points  or  broaches  wrapped  with  absorbent  cotton  is  not  sufficient. 
All  moisture  should  be  evaporated  with  a  current  of  hot  air  or  by 
the  direct  application  of  heat,  by  means  of  one  of  the  several  forms 
of  metallic  root  driers.  Success  in  filling  canals  depends  much 
upon  the  removal  of  moisture  from  the  tubuli. 

Filling  Canals.  The  object  is  to  seal  the  ends  of  the  tubuli, 
and  stop  the  apical  foramina  against  the  entrance  of  anything 
which   might    favor    putrefactive    changes.      The   requisites  for  a 


STERILIZING    CANALS. 


49 


canal  filling  material  are  that  it  should  be  nonirritant  if  forced 
through  the  apical  foramina ;  it  should  be  capable  of  easy  intro- 
duction into  intricate  canals  ;  it  should  be  indestructible  under 
the  conditions  in  which  it  is  placed,  and  it  should  possess  the 
power  of  preventing  putrefaction  of  the  remaining  fibrillae.  The 
materials  used  are  gutta-percha,  wood,  copper,  gold  or  aluminum 
points,  and  chloro-percha,  oxyphosphate  or  oxychloride  of  zinc. 

CANALS     CONTAINING     PUTRESCENT     PULPS. 

Render  Inert  the  Contents  of  the  Canals.  Canals  treated  under 
this  head  contain  decomposed  pulp  tissue,  which  may  be  either 
moist   or   dry,  but   is   always   septic.     The   danger  of   crowding  or 


185 

pumping  some  portion  of  this  septic  matter  through  the  apical 
foramina  makes  it  advisable  to  render  it  inert,  aseptic,  before 
attempting  its  removal.  This  may  be  accomplished  by  the  pre- 
sentation of  some  substance,  one  element  of  which  possesses  a 
strong  affinity  for  decomposed  tissue.  Two  compounds  of  this 
nature  are  kalium  natrium  and  h3'drogen  dioxide.  The  latter  is 
the  more  desirable,  as  its  action  is  less  violent,  and  it  does  not 
leave  a  solid  residue.  If  the  preparation  of  H^  O^,  known  as 
pyrozone,  three  per  cent,  is  applied  slowly,  without  pressure,  the 
contents  of  the  canals  are  graduall}^  asepticised,  and  the  subse- 
quent cleansing  made  easy. 

Refnove  Consents  of  Canais.  After  the  treatment  with  pyrozone, 
by  means  of  hooked  extractors  and  fine  Swiss  broaches  wrapped 
with  cotton,  the  canals  are  easily  cleared  of  their  contents.     Always 


50  WRAPPING  BROACHES. 

use  the  greatest  care  to  avoid  pumping  anything  through  the 
foramina. 

Reaming.  The  same  rules  apply  as  in  the  case  of  recently 
devitalized  pulps. 

Render  Aseptic  This  is  accomplished  by  sealing  into  the 
canals  some  antiseptic  and  germicide.  Among  the  many,  we  notice 
bichloride  of  mercury,  carbolic  acid,  oil  of  cassia,  and  Black's 
"one,  two,  three,"  the  formula  for  which  is  : 

Carbolic  acid  (melted  crystals) 1  part. 

Oil  of  cassia 2  parts. 

Oil  of  wintergreen 3  parts. 

Mix  the  oils  and  add  the  melted  carbolic  acid  crystals. 

When  oils  are  used  the  tooth  should  be  desiccated  be- 
fore their  application.  If  the  antiseptic  has  an  affinity  for  water 
this  is  not  so  important.  The  application  should  remain  in  the 
canal  for  a  sufficient  length  of  time,  and  should  be  repeated  until 
asepsis  is  assured. 

Dry  Canals.  The  rules  given  for  teeth  in  which  the  pulps 
have  been  recently  devitalized  apply  with  equal  force. 

Fill  Canals.  If  there  is  no  pericemental  complications  tlie  canals 
may  be  filled  as  soon  as  asepsis  is  coinplete. 

PRACTICAL    EXERCISES. 

Wrapping  Broaches.  Thorough  practice  in  covering  smooth 
broaches  with  cotton  is  necessary  to  enable  the  student  to  use 
these  valuable  adjuncts  without  making  pistons  of  them. 

Select  a  small  broach,  lay  a  few  fibers  of  cotton  on  the  ball  of 
the  index  finger,  rest  the  broach  upon  it  in  such  a  way  that  the  cot- 
ton will  project  a  little  beyond  the  point  of  the  broach  ;  then  roll 
the  broach  to  the  right,  between  the  thumb  and  finger,  bringing 
pressure  first  upon  the  point,  continuing  until  the  cotton  covers  the 
whole  length  of  the  broach.  This  prevents  the  point  from  being 
uncovered  when  inserting  the  broach  into  a  canal  and  insures  the 
even  covering  of  the  whole  broach.  Emphasis  is  laid  upon  the 
necessity  for  using  small  broaches,  especially  for  cleansing  canals 
of  putrescent  contents. 

Using  Broaches.  After  enlarging  the  openings  into  the  pulp 
chambers  of  the  several  teeth  in  the  articulator,  which  have  been 
selected,  moisten  the  dried  pulps  to  soften  them  ;  for  this  purpose 
dilute  alcohol,  cassia  water,  or  pyrozone  may  be  used.    Care  should 


REAMING,    DRYING   AND   FILLING    CANALS. 


51 


'!(! 


186 


be  exercised  not  to  insert  explorers  or  other  instruments  into  the 
canals  before  using  the  broach.  The  first  attempt  at  extracting  a 
pulp  should  be  in  an  upper  incisor  or  cuspid. 

A  fi)ie  barbed  broach  should  be  presented  with  its 
barbs  against  the  walls  of  the  canal,  and  inserted  until  its 
point  reaches  the  apical  end  of  the  canal  ;  give  one  or  two 
turns  to  the  right  and  withdraw  it  carefully.  The  canals  of 
t?ie  other  teeth  may  then  be  operated  upon  in  like  manner. 
In  canals  where  the  barb  fails  to  remove  all  of  the  pulp, 
or  in  ver}'  small  canals,  the  small  hooked  extractors  may 
be  used.  These  will  not  permit  of  so  much  rotation.  The 
canals  should  be  further  cleansed  with  pyrozone,  applied 
with  a  platinum-iridium  broach  for  the  smaller  canals,  and 
a  wooden  broach  for  the  larger  ones.  Japanese  tooth- 
picks serve  this  purpose  nicely.  Steel  broaches  or  instru- 
ments should  never  be  used  with  pyrozone. 

Reajiiing.  Such  small  canals  as  are  round  or  nearly  so, 
may  be  enlarged  with  the  reamers  Fig.  86,  used  in  the  re- 
volving head  bur  holder.  The  exercise  may  be  continued 
with  larger  reamers  in  larger  canals  which  are  supposed 
to  have  contained  putrescent  pulps.  One  or  two  roots  may 
be  prepared  for  the  reception  of  a  dowel  pin,  by  enlarging 
their  canals  with  the  reamer  Fig.  85. 

Drying.  The  canals,  which  have  been  moist  up  to  this 
time,  may  now  be  dried;  first,  with  slender  conical  points 
cut  from  firm,  fine  grained  blotting  paper,  then  with  absorb- 
ent cotton  on  Swiss  broaches;  completing  the  operation 
with  the  canal  drier.  Fig.  186. 

Filling.  Four  methods  of  filling  will  be  given.  First, 
with  gutta-percha  points  moistened  with  eucalyptus  oil; 
Second,  with  gutta-percha  points  and  chloro-percha;  Third, 
with  parafine  and  copper  points;  Fourth,  with  chloro-percha 
and  gutta-percha  point  at  apex,  remainder  of  canal  with 
oxychloride  of  zinc.  Preparator}'  to  filling,  a  student  should 
make  some  chloro-percha  by  dissolving  shavings  of  pink 
base  plate  guttapercha  in  chloroform,  and  cut  some  small 
triangular  pieces  of  pink  base  plate  and  roll  into  slender 
conical  points  on  a  warm  glass  slab.  Roll  some  similar  points  of 
parafine.  With  a  file  make  some  very  small,  slender  points  of  cop- 
per.     Flood  one  of  the  larger  round  canals  with  eucalyptus  oil; 


53  FILLING    CANALS. 

dry  canal  and  warm  it  with  the  root  drier;  dip  a  gutta-percha  point 
in  eucalyptus  oil,  ignite  the  oil  and  allow  it  to  burn  off,  dip  again 
in  the  oil  and  insert  it  in  the  warm  canal,  driving  it  home  with  a 
blunt,  strong  broach.  Into  another  canal,  pump  some  chloro-percha 
with  a  fine  smooth  broach;  dip  a  gutta-percha  point  in  the  chloro- 
percha  and  force  it  home.  In  one  of  the  very  small  canals,  place 
one  of  the  parafine  points,  melting  it  and  causing  it  to  flow  into 
the  canal  with  the  root  drier;  heat  one  of  the  copper  points  and 
force  it  into  the  canal.  Select  a  canal  in  which  the  pulp  was  sup- 
posed to  be  putrescent;  fill  its  apical  portion  with  chloro-percha 
and  gutta-percha  point,  and  the  remaining  portion  with  oxychloride 
of  zinc. 


CHAPTER   IV. 


CLASSIFICATION    AND    PREPARATION    OF    CAVITIES. 

Cavities  of  decay  which  are  found  on  the  surfaces  of  all  the 
teeth,  are  the  result  of  two  great  predisposing  causes;  first,  struc- 
tural imperfections;  second,  prolonged  contact  of  any  surface  with 
the  results  of  fermentation,  or  with  the  secretions  from  diseased 
tissues.  Structural  imperfections  result  from  imperfect  coalescence 
of  the  enamel,  usually  at  the  point  of  union  of  the  several  develop- 
mental lobes;  or  from  arrested  development.  Consequently  they 
occur  on  surfaces  where  grooves  are  sharpest  and  deepest,  or  in 
those  grooves  which  cross  labial  or  lingual  surfaces  at  right  angles 
with  the  long  axis  of  the  tooth,  indicating  an  arrest  of  development 
at  some  period  in  the  growth  of  the  tooth. 

As  the  occlusal  surfaces  are  usuall}^  kept  clean  by  the  act  of 
mastication,  and  the  greater  portion  of  the  labial  or  buccal  and 
lingual  surfaces  are  cleansed  by  the  action  of  the  tongue  and  lips, 
we  naturally  turn  to  the  proximate  surfaces,  and  to  that  portion  of 
the  labial  and  lingual  surfaces  next  to  the  gums,  to  find  cavities 
which  are  the  result  of  the  second  cause.  Although  a  satisfactory 
classification  on  this  basis  is  difficult,  separation  into  classes  is 
necessary  for  purposes  of  study.  We  will  classify  according  to  the 
form  and  location  of  the  cavity  and  the  completed  filling.  Cavi- 
ties upon  all  surfaces  other  than  proximate  are  formed  and  filled 
under  the  same  general  rules.  In  cavities  upon  the  proximate  sur- 
faces of  incisors  and  cuspids,  these  rules  are  modified  by  the  loca- 
tion and  shape  of  the  surface  and  the  extent  of  the  cavity.  For 
similar  reasons,  cavities  upon  the  proximate  surfaces  of  bicuspids 
and  molars  are  governed  by  rules  peculiar  to  themselves.  These 
facts  form  the  basis  for  our  classification: 

(Blackboard  Diagram.) 

f      A.     Cavities  arising  from  structural  imper- 
fections in  pits  and  fissures. 

1      All  cavities  on  any 
Class  1.      -|  surface  other    than  ■{       B.     Cavities    on   labial,   buccal  or   lingual 
proximate.  surfaces,    caused    by    contact  with  secretions 

from  diseased  tissue,    or   the  products   of  fer- 
mentation. 


54 


CLASSIFICATION   OF   CAVITIES. 


Class  2. 


l'      A.     Cavities  which  do  not  involve  the  me- 
sial or  distal  angle, 
f      All  cavities  on  the  | 
j  proximate    surfaces -{ 

1  of  incisors  and  cus-  |       B.     Cavities  which  involve   the  restoration 
lipids.  I  of  the  mesial  or  distal  angle. 

I 

f  A.  Cavities  which  include  the  marginal 
ridge,  but  do  not  involve  any  sulci  or  grooves 
upon  the  occlusal  surface. 


Class  3. 


(      All  cavities  on  the 
I  proximate    surfaces^ 
I  of    biscuspids     and 
[  molars. 


I 


B.  Cavities  which  involve  not  only  the 
marginal  ridge,  but  also  sulci  or  grooves  upon 
the  occlusal  surface. 


Fig  187 


d 


^A\3 


Fig.  188 

As  fillings  in  cavities  of  the  first  class  are  upon  either  plane, 
slightly  convex,  or  slightly  concave  surfaces  they  are  simple  inlays. 
Any  surface  which  is  to  receive  an  inlay  must  have  a  recess  for  its 
reception;  this  recess  must  correspond  in  outline  with  the  inlay, 
and  may  be  called  a  mortise.  Some  of  the  forms  of  inlays  for 
cavities  of  the  first  class  are  shown  in  Fig.  187.  When  the  inlay  is 
in  one  piece,  as  is  necessary  if  it  be  made  of  glass  or  porcelain,  the 
mortise  should  have  parallel,  perpendicular  sides,  Fig.  188,  a. 
Such  inlays  are  held  in  position  by  adhesion  or  by  the  perfection 
of  their  adaptation  to  the  mortise.  Where  the  inlay  is  introduced 
in  pieces  or  sections,  or  in  a  plastic  condition,  the  mortise  is  given 
retaining  shape,  /.  e.,  enlarged  in  some  direction  in  its  interior. 
There  may  be  grooves  on  one  or  more  sides,  as  in  b  and  <r.  Fig.  188. 
These  are  grooved  mortises.  One  or  more  of  the  sides  may  be 
sloped,  joining  the  base  at  an  acute  angle;  as  in  ^  and  ^,  Fig.  188. 
These  are  dovetailed  mortises.      For  materials  inserted  while  in  a 


MORTISES. 


55 


plastic  condition,  the  mortise  may  be  rounded  in  form,  as  in/.  Fig. 
IftB.  If  cavities  in  teeth  were  given  any  of  the  foregoing  forms, 
except  it  might  be  that  shown  in  a,  Fig.  188,  tlie  structure  of  the 
enamel  is  such,  that  fracture  or  chipping  of  the  enamel  margins 
would  occur  when  subjected  to  any  force  or  strain.  For  this  rea- 
son, the  retaining  shape,  or  dovetail  of    the  mortise  is  made  in  the 


riG.190>^ 


These  cuts  are  made  from  photomicroe;raphs,  3  in.  objective.  In  outline  they 
are  faithful  reproductions.  The  structure  is  entirely  diagrammatic.  All  the  longi- 
tudinal sections  shown,  except  Figs.  213  and  327,  which  are  made  from  drawings, 
are  made  in  the  same  way. 

dentine,  a,  Fig.  189,  and  a,  Fig.  190;  the  enamel  is  protected  from 
fracture  by  beveling  it,  as  in  b,  Fig.  189,  and  b,  Fig.  190.  For  con- 
venience the  retaining  shape  in  the  dentine  will  be  called  the  denti- 
nal pyramid,  c,  Fig.  189,  and  c,  Fig.  190,  and  the  enamel  bevel  will 
be  called  the  enamel  pyramid,  d,  Fig.  189,  and  d,  Fig.  190.  In  the 
dentinal  pyramid  the  amount  of  retaining  shape,  or  angle  of  the 
sides  of   the  pyramid  with    its  base,  depends  upon   the  strain   to 


56  CAVITIES,    CLASS  i. 

which  the  inla}',  or  filling  is  to  be  subjected.  The  sharpness  of 
bevel  of  the  enamel  depends  upon  the  character  of  the  material  of 
which  the  inlay,  or  filling  is  composed;  the  form  shown  in  b,  Fig. 
189,  is  practicable,  if  the  material  possesses  ductility,  tenacity,  or 
edge  strength,  as  gold;  while  the  form  shown  in  b,  Fig.  190,  is  nec- 
essary if  the  material  does  not  possess  these  qualities,  as  tin,  amal- 
gam, cement,  or  gutta-percha. 

Taking  the  teeth  in  their  numerical  order,  we  find  cavities  of 
division  A,  class  1,  upon  the  lingual  surfaces  of  the  upper  incisors 
and  cuspids,  when  there  is  a  sharp  groove  at  the  base  of  the  linguo- 
gingival  ridge,  or  sharp  grooves  crossing  this  ridge.  Figs.  191   to 

197.  Cavities  in  grooves  or  pits  marking  arrested  development 
also  occur  upon  these  surfaces,  in  the  middle  or  incisal  third,  Fig. 

198.  The  labial  surfaces  of  these  teeth  seldom  have  cavities  aris- 
ing from  structural  imperfections  except  in  those  pits  and  grooves 
which  mark  arrested  development.  Fig.  199.  The  lower  incisors 
and  cuspids  seldom  have  cavities  of  division  A,  class  1.  The  labial 
surfaces  of  upper  incisors  and  cuspids  often  have  cavities,  of  di- 
vision B,  class  1,  see  Figs.  200  and  201.  The  lingual  surfaces 
seldom  have  cavities  of  this  division.  The  labial  surfaces  of  lower 
incisors  and  cuspids  sometimes  show  cavities  of  division  B,  class 
1;  the  lingual  surfaces  almost  never.  On  the  occlusal  surfaces  of 
the  upper  bicuspids  we  find  cavities  in  pits  at  the  junction  of 
grooves,  and  in  fissures  wherever  grooves  are  sharp  and  deep,  Figs. 
202  and  203.  The  buccal  and  lingual  surfaces  of  upper  bicuspids 
rarely  have  grooves  marking  arrested  development,  but  cavities  of 
division  B,  class  1,  occur  on  the  buccal  surfaces  in  the  gingival 
third,  Fig.  204;  but  seldom,  if  ever,  on  the  lingual  surfaces. 
Cavities  of  division  A,  class  1,  occur  occasionally  on  the  oc- 
clusal surfaces  of  lower  first  bicuspids,  and  frequently  on  these 
surfaces  of  the  lower  second  bicuspids,  Figs.  205,  and  206.  The 
buccal  surfaces  of  the  lower  bicuspids  often  have  cavities  of  di- 
vision B,  class  1,  in  the  gingival  third;  the  lingual  surfaces  seldom, 
if  2ver. 

The  occlusal  surfaces  of  upper  molars  have  cavities  of 
division  A,  class  1,  at  the  junction  of  grooves  and  in  deep  grooves, 
Figs.  20*7,  and  208.  The  buccal  surfaces  of  the  upper  molars  sel- 
dom show  pits  or  fissures,  except  in  poorly  developed  first  molars, 
which  sometimes  result  from  an  infantile  sickness;  but  the  lingual 
surfaces    frequently  have   cavities   in    pits   and   fissures,  especially 


213 


Cuts  191  lo  212  inclusive,  and  214  and  215,  are  made  from  photographs  of 
natural  teeth.  They  are  accurat-  reproductions  in  outline,  but  they  are  enlarged 
about  one  and  a'half  times.  The  unprepared  cavities  are  shown  as  they  appear 
in  the  teeth.  ^ 


58 


CAVITIES,   CLASS  i. 


when  the  disto-lingual  groove  of  the  buccal  surface  crosses  over  to 
the  lingual  surface,  or  when  the  lingual  groove  terminates  in  a  pit, 
Fig.  209.  The  lower  molars  have  cavities  of  division  A,  class  l,on 
the  occlusal  surfaces,  under  the  same  conditions  as  those  noted  for 
the  upper  molars,  Figs.  210  and  211;  the  buccal  surfaces  have 
cavities  of  division  A,  class  1,  in  the  buccal  groove,  and  occasional- 
ly in  the  disto-buccal  groove,  Fig.  212.  Cavities  of  division  B, 
class  1,  are  found  in  the  gingival  third  of  the  buccal  surfaces  of 
both  upper  and  lower  molars,  but  not  upon  the  lingual  surfaces, 
except  in  cases  of   recession  of  the  gums.     In  fact,  the  buccal  and 


213  214  315 

lingual  surfaces  of  all  of  the  teeth,  upper  and  lower,  are  liable  to 
have  cavities  of  division  A,  class  1,  when  the  gums  have  receded 
sufficiently  to  expose  the  gingival  line. 

In  cavities  of  division  A,  class  1,  the  general  rule  for  cavity 
outline  is,  that///^  should  be  enlarged  until  sound  walls  are  obtained, 
and  fissures  should  be  cut  to  the  end,  or  until  the  fissure  becomes  a 
groove.''  If  gold  or  tin  is  used  in  filling,  the  walls  of  the  cavity  for 
the  dentinal  pyramid  should  be  shaped  as  in  a,  Fig.  189,  and  a, 
Fig.  1903^.  For  gold,  the  bevel  for  the  enamel  pyramid  maybe  as 
great  as  in  b,  Fig.  189,  if  the  location  of  the  cavity  makes  it  desir- 
able. For  tin,  the  enamel  bevel  should  be  as  shown  at  b,  Fig.  190, 
or  b.  Fig.  1901^.  If  amalgam,  cement,  or  gutta-percha,  is  the  ma- 
*Lines  have  been  placed  on  all  the  cuts  to  indicate  the  outlines  of  the  pre- 
pared cavities. 


CAVITIES,    CLASS  2.  59 

terial  employed,  the  dentinal  pyramid  may  be  shaped  as  in  a,  Fig. 
190;  while  the  enamel  pyramid  should  have  no  more  bevel  than  is 
shown  in  b,  Fig.  190,  or  b,  Fig.  1901^. 

In  cavities  of  division  B,  class  1,  the  cutting  mesially,  distally, 
and  toward  incisal  portion,  should  be  enough  to  insure  sound  walls, 
and  true  lines  of  beauty;  cut  rootward  sufficiently  to  place  the  cer- 
vical margin  beneath  the  free  margin  of  the  gum.  Fig.  213,/.  If 
this  is  not  done,  the  result  would  be  as  is  shown  at  <?,  Fig.  213. 
Where  the  free  margin  of  the  gum  is  long,  it  is  not  necessary  to 
establish  the  cervical  margin  of  the  cavity  in  the  cementum,  as 
seen  at/.  Fig.  213.  A  short  triangle  of  enamel,  such  as  is  shown 
at  e,  Fig.  213,  should  never  be  left.  In  rare  instances,  as  in  Fig. 
201,  it  is  not  necessary  to  place  the  cervical  margin  of  the  cavity 
beneath  the  gum.  The  mesial  and  distal  margins  of  these  cavities 
should  cross  the  line  of  the  gum  margin  as  nearly  at  right  angles 
as  possible,  Fig.  214,  in  order  that  such  triangular  areas  of  enamel 
as  are  shown  in  P'ig.  215,  shall  not  be  left.  This  class  of  cavities 
are  especially  annoying  when  there  is  a  tendency  to  inflammation 
of  the  gingival  border,  or  where  there  is  recession  of  the  gums. 
Normally,  theenamel is  slightly  oveTlappedby  the  cementum, a,  Fig. 
213,  but  in  many  specimens  this  condition  does  not  exist,  ^,  Fig.  218. 
When  from  any  cause  such  points  are  exposed  by  recession  of  the 
gums,  such  structural  imperfections  are  a  predisposing  cause  of 
decay,  d,  Fig.  213. 

Cavities  of  the  second  class  have  two  dentinal  pyramids;  one 
with  its  base  rootward,  b,  Fig.  216,  and  c,  Fig.  217;  the  other  with 
its  base  toward  the  pulp,  a,  Fig.  218,  a,  Fig.  219,  and  a,  Fig.  220. 
They  have  one  enamel  pyramid  with  its  apex  pulpward,  b,  Fig.  218, 
b,  219,  and  d,  220.  As  these  cavities  are  on  the  proximate  surfaces 
of  the  conical  teeth,  they  have,  when  prepared,  the  pyramidal  out- 
line seen  in  Figs.  216,  and  217.  They  seldom  occur  under  good 
hygienic  conditions,  except  there  be  broad  contact,  as  in  Fig.  221, 
or  when  the  festoon  of  the  gum  is  withdrawn  from  the  interdental 
space.  It  is  necessary  to  establish  the  cavity  margins  outside  of 
the  point  of  contact,  with  the  cervical  margin  beneath  the  border 
of  the  gum. 

In  division  A,  class  2,  cavities  usually  appear  as  in  a,  Fig.  216; 
when  prepared,  they  should  appear  as  in  b.  Fig.  216  ;  the  form  of 
the  dentinal  and  enamel  pyramids  is  seen  in  Figs.  21S,  219,  and 
220.  The  labial  margin  should  not  only  be  outside  the  point  of 
contact,  but  should  extend  so  far  upon  the  labial  surface,  and  have 


317 


These  cuts,  as  well  as  Figs.  223  to  226  are  made  from  photographs  of  teeth 
having  cavities  as  shown. 


*riG.2l8    y^ 


t  Rg.  219 


.b 


d-— 


a — a 


aao 


319?^ 


*This  cut,  in  common  with  all  the  transverse  sections  shown,  was  made  from 
a  photograph  of  a  section  of  a  tooth,  and  is  accurate  in  outline  ;  structure  dia- 
grammatic.     This  section  was  cut  from  an  incisor  at*?,  Fig.  219>^. 


tThis  section  was  cut  from  an  incisor  at  /',  Fig.  219>^. 


LABIAL    CAVITIES. 


61 


such  outline  as  to  prevent  tlie  gold  from  being  in  shadow  ;  if  in 
shadow,  it  appears  as  a  dark  line.  The  lingual  margin  should 
extend  so  far  upon  the  lingual  surface  as  to  insure  the  cleansing  of 
this  margin  by  the  action  of  the  tongue.  The  occlusal  margin 
should  have  such  enamel  bevel  as  will  bring  it  outside  the  point 
of  contact.  These  various  points  are  illustrated  in  Figs.  221 
and  222. 


These  cuts  are  reproductions  of  teaching  charts  by  Dr.  W.  J.  Brady.     Fig.  222 
shows  ideal  contact ;   Fig.  221  shows  one  of  the  many  departures  from  the  ideal. 

The  line  of  demarcation  between  division  A  and  division  B, 
class  2,  is  a  disputed  point.  Which  cavities  to  leave  in  division 
A,  and  which  to  place  in  division  B,  by  involving  the  mesial  or  the 
distal  angle,  must  be  left  to  the  judgment  of  the  operator.  The 
chief  factors  are  the  strength  of  this  angle  after  the  decay  is  re- 
moved, the  shape  and  structure  of  the  tooth,  ami  the  manner  of 
occlusion.  The  general  outline  of  the  prepared  cavity,  as  seen  in 
c.  Fig.  217,  is  the  same  as  that  for  division  A,  as  seen  in  b,  Fig. 
216.  except  that  more  of  the  labial  and  lingual  surfaces  are  sac- 
rificed, b,  Fig.  217,  and  the  dentinal  pyramid  has  more  retaining 
shape.      Having  determined  to  involve  the  mesial  or  distal  angle, 


63 


AUXILIARY  DOVETAIL. 


enough  tooth  substance  naust  be  sacrificed  to  allow  sufficient  gold 
in  the  incisal  portion  of  the  filling  to  resist  the  strain  of  masti- 
cation ;  and  the  cavity  must  have  enough  retaining  shape  to  re- 
sist this  strain.  The  usual  form  of  cavity  preparation  is,  in  the 
main,  as  shown  in  Fig.  217,  and  in  the  outline  illustrations,  Figs. 
218   and   219. 

In  those  teeth  which  are  long  and  thin,  or  where  the  occlu- 
sion is  such  that  the  teeth  will  in  time  become  abraded,  the  form 
of  preparation  just  described  is  open  to  objections.  In  the  first 
instance,  the  form  of  the  tooth  makes  it  impossible  to  secure  suffi- 
cient retaining  shape  in  the  incisal  third.      In  the  second  instance 


such  retaining  shape  is  lost  by  the  general  abrasion.  It  is  also 
difficult  to  fill  that  portion  of  the  dentinal  pyramid  in  the  incisal 
third  of  a  thin  incisor.  In  these  cases,  an  auxiliary  dovetail  may 
be  cut  upon  the  lingual  surface,  as  in  Fig.  223  :  or  in  addition  to 
this,  a  tenon  may  be  prepared  to  dovetail  into  the  filling,  as  in 
<r,  Fig.  219.  The  tooth  is  cut  off  at  the  incisal  third,  and  the 
enamel  grooved,  as  in  Figs.  224  and  225  ;  also  c,  Fig.  219.  The 
dentinal  pyramid  at  the  base  of  the  filling,  in  the  cervical  third,  is 
seen  in  c,  Fig.  218.*  A  form  of  preparation  for  cavities  in  distal 
surfaces  of  upper  cuspids,  is  that  of  cutting  a  dovetail  on  the  lin- 
gual surface.      Fig.  222. 

Cavities  of  the  third  class,  occurring  upon  somewhat  broad 
and  flattened  contact  surfaces,  are  seldom  confined  to  the  proximate 
surfaces.  They  usually  involve  the  mesio-marginal  or  disto-mar- 
ginal  ridge.  Where  the  adjoining  tooth  has  been  extracted,  these 
cavities,  in  many  cases,  may  be  filled  without  cutting  through  the 
ridge  to  the  occlusal  surface.     In  such  cases,  the  rules  for  prepara- 

■"Thcsc  forms  of  preparation  were  suggested  by  Dr.  I.  C.  St.  John.     See  Den- 
tal Cosmos,  Vol.  XXXVI.,  p.  198. 


CAVITIES,   CLASS  3.  63 

tion  are  the  same  as  for  the  preparation  of  a  cavity  upon  any  plane 
or  slightly  convex  surface. 

The  usual  form  of  preparation  for  cavities  of  division  A,  class 
3,  is  shown  in  b  and  c,  Fig.  226.  There  are  two  dentinal  pyra- 
mids, one  with  its  base  rootward,  a.  Fig.  227;  the  other  with  its 
base  pulpward,  a.  Fig.  228.  The  form  of  the  teeth  gives  two 
enamel  pyramids,  one  with  its  apex  pulpward,  b.  Fig.  228,  the  other 
with  its  apex  rootward,  b,  Fig.  227.  In  division  B,  class  3,  a 
simple  cavity  in  a  sulcus  or  groove  upon  the  occlusal  surface  is 
combined  with  the  cavity  seen  in  Fig.  b  and  c,  Fig.  226.  This 
forms  an  auxiliary  dovetail,  which  has  the  same  pyramidal  form  in 
dentine  and  enamel  as  is  given  to  cavities  of  division  A,  class  1. 
Care  should  be  exercised  that  the  points  e  andy".  Fig.  229,  should 
be  the  deepest,  as  this  form  gives  a  firm  "seat"  for  the  filling,  en- 
abling it  the  better  to  resist  the  strain  brought  upon  it  at  g,  and  //, 
Fig.  229.  The  various  points  of  preparation  for  cavities  of  class 
3,  are  shown  in  Figs.  226  to  229. 

Emphasis  should  be  placed  upon  the  necessity  for  flat  bases  to 
the  dentinal  pyramid,  with  the  plane  walls  rising  at  a  slightly 
acute  angle  with  the  base,  in  all  classes  of  cavities  where  gold  or 
tin  is  used;  and  upon  the  latitude  which  may  be  permitted  when 
plastics  are  employed.  In  the  forming  of  the  enamel  pyramid, 
stress  should  be  placed  upon  the  fact  that  a  broad  bevel  must  not 
be  made  for  any  material  but  gold.  All  cavity  outlines  should  be 
on  true,  smooth  lines,  /.  <?.,  perfectly  straight  lines  and  true  curves. 
Jagged  outlines  not  only  detract  from  the  beauty  of  the  operation, 
but  increase  the  difficult}^  of  condensing  and  finishing  the  filling. 
All  enamel  margins  should  be  carefully  smoothed,  for  the  same 
reasons.  All  cavities  should  be  prepared  step  by  step:  1st, 
establish  outline  of  cavity;  2d,  remove  deca}';  3d,  make  retaining 
shape;   4th,  bevel  and  finish  enamel  margins. 

PRACTICAL    EXERCISES. 

The  extreme  difficulty  of  preparing  typical  cavities  in  dried 
teeth,  makes  it  desirable  to  limit  such  cavity  preparation  in  the 
teeth  mounted  in  the  articulator.  Only  one  cavity  of  each  division 
of  the  several  classes  need  be  required.  In  order  that  the  student 
may  have  the  necessary  practice  in  cavity  preparation,  some  ma- 
terial should  be  chosen  which  can  be  cut  more  easily  than  the  dry 
teeth.      Dice,  and  toothbrush  handles  of  bone   are  employed,   but 


64  PREPARING    CAVITIES. 

the  coarseness  of  the  grain  in  the  bone,  makes  it  difficult  to  get  nice 
cavity  margins.  Experiments  with  celluloid  have  progressed  so 
far  as  to  indicate  that  this  material  may  be  so  prepared  as  to  meet 
the  requirements.  It  may  be  easily  moulded  into  tooth  form, 
which  will  be  a  great  advantage.  Haviag  selected  some  material, 
cavities  should  be  prepared  in  it  before  attempting  to  prepare  any 
in  the  teeth. 

Exercise  1.  Prepare  on  plane  surfaces  of  bone  or  celluloid 
five  cavities  similar  in  outline  to  those  shown  in  Fig.  187,  having  a 
depth  of  one-eighth  inch,  with  plane  walls  rising  from  the  plane 
floor  of  the  cavity  at  slightly  acute  angles,  as  in  e,  Fig.  188.  These 
cavities  are  designed  for  filling  with  tin.  In  the  preparation  of 
them,  such  chisels  as  Nos.  13,  15  and  20,  and  such  excavators  as 
Nos.  14,  44,  45,  4G,  47  and  51,  may  be  used.  If  cavities  are  desired 
for  plastics,  others  may  be  prepared  having  similar  outline  and 
depth,  with  such  shapes  as  that  shown  in  /,  Fig.  188.  For  such 
cavities  the  spoon  excavators.  Figs.  50,  51,  52,  65,  67  and  68,  may 
be  used. 

Exercise  2.  Prepare,  for  gold  or  tin,  one  cavity  of  division  A, 
class  1,  and  one  of  division  B,  class  1,  in  some  tooth  in  the  articu- 
lator. One  of  each  division  may  also  be  prepared  for  plastic  fill- 
ing. In  this  exercise,  the  same  instruments  may  be  \ised  as  in  the 
first  exercise,  and  the  operation  should  be  performed  step  by  step 
as  outlined. 

Exercise  3.  In  the  edge  of  the  toothbrush  handle,  at  the  thin 
end,  where  it  resembles  the  proximate  surface  of  an  incisor,  or  in 
incisor  teeth  of  celluloid,  prepare  one  cavity  of  division  A,  class  2, 
for  tin,  and  one  for  plastics  ;  also  one  for  gold  or  tin,  and  one  for 
plastics  of   division  B,  class  2. 

Exercise  4.  Prepare  one  cavity  of  division  A,  class  2,  for  tin, 
in  one  of  the.  incisors  in  the  articulator.  Prepare  one  cavity  of 
division  B,  class  2,  for  plastics,  in  another  incisor  in  the  articulator. 
Prepare  one  cavity,  division  B,  class  1,  in  an  incisor,  cutting  an 
auxiliary  dovetail  on  the  lingual  surface.  In  these  two  exercises, 
the  student  may  use,  in  addition  to  the  instruments  already  em- 
ployed, the  burholder.  Fig.  82,  with  burs  of  the  proper  size,  shaped 
like  Figs.  88,  94,  95,  96,  and  97.  These  operations  also  should  be 
performed  step  by  step. 

Exercise  5.  In  the  square  end  of  the  toothbrush  handle,  or  in 
a  bicuspid  or  molar   of    celluloid,  prepare  one   cavity  for   tin,  and 


,  .    .     ■         ^l     f  g 

This  section  gives  a  buccal  view  of  an  upper  first  bicuspid. 


66  PREPARING   CAVITIES. 

one  for  plastics,  of  division  A,  class  3.  In  the  same  material,  pre- 
pare one  cavity  for  tin  and  one  for  plastics  of  division  B,  class  3. 

Exercise  6.  In  a  bicuspid  or  molar,  in  the  articulator,  prepare 
for  plastics,  one  cavity  of  division  A,  and  one  of  division  B,  class 
3.  The  instruments  ernployed  for  the  previous  exercises  are  the 
ones  to  be  used  for  these  two,  and  the  operation  should  be  per- 
formed step  by  step  as  before. 

When  operating  upon  teeth  -in  the  articulator,  it  should  be 
fixed  by  means  of  the  bolt,  so  that  the  incisors  are  opened  two 
inches.  See  Fig.  1,  A.  In  all  the  exercises,  the  outlines  of  the 
cavities  should  be  laid  out  symmetrically  with  true  lines.  Espe- 
cial care  should  be  observed  that  the  margins  of  the  cavity  in 
the  bone  or  celluloid,  as  well  as  in  the  teeth,  are  smooth,  and 
the  margins  of  enamel  in  the  teeth  are  given  the  proper  bevel. 
The  same  precautions  should  be  observed  against  penetrating  the 
pulp  chamber  as  in  clinical  practice.  If  an  exposure  is  made, 
this  cavity  should  be  prepared  with  a  view  to  capping  the  pulp, 
as  described  in  the  next  chapter.  The  teacher  will  find  that  the 
student  understands  the  forms  of  cavit}^  preparation  much  better 
if  he  prepares  each  cavity  before  them,  in  a  collossal  clay  model, 
using  enlarged  instruments.  If  time  and  conveniences  will  per- 
mit, the  students  may  themselves  prepare  cavities  in  clay  teeth 
which  they  have  modeled. 


CHAPTER  V. 


PULP   TREATMENT. 
CONSERVATIVE    AND    RADICAL 

Conservative  treatment:  The  points  to  be  considered  first  are 
the  form,  location,  and  environment  of  the  pulp;  its  composition 
and  structure;  its  function  and  relations  to  the  dentine;  the  condi- 
tions to  which  it  is  sensitive;  its  natural  protection  and  its  behavior 
when  this  natural  protection  is  lost,  and  its  behavior  under  arti- 
ficial protection.  The  cutting  of  sections  and  printing  of  silhou- 
ettes gives  the  student  the  best  opportunity  possible  for  becoming 
familiar  with  the  form,  location  and  environment  of  the  pulp.  The 
pages  of  his  printing  book,  of  which  Fig.  6  is  an  example,  furnish 
a  record  which  is  an  ever  ready  reference.  They  show  that  the 
outline  of  the  pulp  chamber,  which  defines  the  form  of  the  pulp 
itself,  follows  the  outline  of  the  teeth  in  a  general  way.  The}'  show 
also  the  location  of  the  pulp  in  the  tooth  and  that  it  is  surrounded 
by  unyielding  walls;  imprisoned  in  a  cell  of  solid  masonry.  This 
information  the  student  must  possess  if  he  is  to  prepare  cavities 
intelligently  and  avoid  accidental  exposures.  In  his  histological 
and  embryological  studies  he  learns  that  the  pulp  is  composed  of 
connective  tissue,  richly  supplied  with  nerves  and  blood  vessels; 
that  it  has  no  lymphatic  system;  that  its  outer  layer  or  coat,  the 
membrana  eboris,  is  composed  of  odontoblastic  cells,  columnar  or 
pear  shaped  in  form,  having  processes  which  fill  the  dentinal  tubuli, 
and  others  which  anastomose  with  other  cells;  that  these  cells  are 
composed  of  protoplasm,  which  is  sensitive  to  heat,  cold,  touch, 
and  various  chemical  substances;  that  the  terminals  of  the  nerves 
of  the  pulp  are  among  these  cells;  that  the  pulp  is  the  formative 
organ  of  the  tooth,  its  function  being  to  build  dentine,  which  func- 
tion ceases  when  the  tooth  is  complete;  however,  under  certain 
conditions  it  is  reawakened.  He  learns  also  that  the  pulp,  pro- 
tected as  it  is  from  contact  of  all  kinds,  is  normall}'  sensitive  only 
to  heat  or   cold,  and   that   because  of  tne    nonconducting    power 


68  FUNCTION  OF  THE  PULP. 

of   enamel,    it   is    protected  from   all   other  changes,  to  which  the 
teeth  are  usually  subjected,  when  the  enamel  is  intact. 

He  learns  from  pathology  that  when  enamel,  which  furnishes 
the  natural  protection  to  the  pulp  and  its  processes  in  the  dentine, 
is  lost,  changes  in  the  pulp  take  place.  That  such  loss  of  tissue 
results  in  irritation  to  the  pulp.  When  this  loss  of  enamel  is  slight, 
the  slight  irritation  consequent,  stimulates  the  activity  of  the 
odontoblastic  cells,  causing  them  to  deposit  calcific  matter, 
secondary  dentine,  within  the  pulp  chamber,  at  the  point  nearest 
the  loss  of  tissue.  The  second  effect  of  irritation  following  greater 
loss  of  protective  tissue,  is  hyperaemia;  the  result  of  this  is  likely 
to  be  a  deposit  of  unattached  calcific  matter  within  the  pulp  in 
the  form  of  pulp  nodules.  The  result  of  continued  or  increased 
irritation  is  inflammation,  which  if  not  arrested  will  result  in  death 
of  the  pulp. 

Clinical  observation  teaches  that  when  the  materials  used  to 
replace  lost  tissue  do  not  protect  the  pulp  from  the  ordinary  ther- 
mal changes  to  which  the  teeth  are  subjected,  the  same  results 
follow  the  various  degrees  of  irritation  as  when  no  restoration  has 
been  made. 

The  following  summary  is  deduced  from  these  facts.  The  pulp, 
properly  speaking,  is  not  confined  to  the  pulp  chamber  and  canals, 
because  of  the  processes  of  the  odontoblastic  cells  which  penetrate 
the  dentine  to  its  periphery.  It  is  not  sensitive  to  ordinary  tem- 
perature when  protected  by  the  normal  thickness  of  enamel,  but 
becomes  sensitive  in  proportion  to  the  loss  of  this  protection. 
When  the  enamel  is  entirel}' gone  at  any  point,  the  exposed  dentine 
is  sensitive  to  all  the  conditions  to  which  protoplasm  is  sensitive. 
Pain  may  occur  and  inflammation  of  the  pulp  ensue,  through  its 
fibrillse  or  odontoblastic  processes,  without  actual  exposure  of  the 
pulp.  The  natural  protection  of  the  pulp,  when  lost,  should  be 
restored  by  such  substances  as  will  most  nearly  fulfill  the  office  of 
the  normal  protection. 

The  conservative  treatment  of  the  pulp  will  be  considered 
under  two  separate  heads,  pulp  protection  and  pulp  capping. 
Pulp  protection  refers  to  the  practice  of  placing  some  noncon- 
ducting substance  between  the  bottom  or  axial  wall  of  the  cavity 
and  the  filling  proper,  in  those  cases  where  there  is  no  exposure 
of  the  pulp.  The  term  "intermediate"  will  be  adopted  to  desig- 
nate   such    nonconducting    substance.     Where    decay    progresses 


CAPPING  MATERIALS.  69 

slowly,  changes  undoubtedly  occur  in  the  pulp  which  lessen  its 
normal  sensitiveness,  the  result  of  the  effort  which  nature  always 
makes  to  repel  disease.  On  this  account  protection  is  not  always 
necessary,  but  in  cases  where  pain  results  from  changes  in  tem- 
perature while  preparing  the  cavit}^  an  "intermediate"  should  pre- 
cede the  filling.  It  may  be  well  to  consider  the  much  discussed 
point  of  leaving  affected  dentine  as  a  protection  to  the  pulp,  rather 
than  to  remove  it  at  the  risk  of  making  an  exposure.  All  cavi- 
ties of  decay  are  infected.  Semidecalcified  dentine  which  ap- 
pears normal  to  the  eye  may  be  penetrated  by  the  microorgan- 
isms of  decay.  Such  dentine  may  be  so  treated  as  to  arrest  the 
further  progress  of  the  affection.  This  is  accomplished  by  steril- 
izing the  affected  dentine.  Hence  we  conclude  that  partially  de- 
calcified dentine  may  be  left  as  a  protection  to  the  pulp  if  it  be 
perfectly  sterilized.  The  student,  however,  should  not  be  misled 
by  this  statement,  and  leave  dentine  which  is  badly  disorganized 
in  an}'  part  of  a  cavit}^  He  should  also  be  sure  that  whatever 
germicide  is  employed  is  ]jft  for  a  sufficient  length  of  time  to 
sterilize  a// of  the  affected  dentine.  It  is  in  fact  good  surgery  to 
sterilize  all  cavities  of  decay. 

The  chief  requisite  in  a  material  for  pulp  protection  is  that 
it  is  a  nonconductor.  The  two  materials  which  possess  this  qual- 
it}'  to  the  fullest  extent  are  gutta-percha  and  asbestos.  Gutta- 
percha is  cut  in  the  form  of  a  wafer  of  sufficient  thickness  for 
the  case  in  hand,  large  enough  to  cover  the  floor  or  axial  wall 
of  the  cavity,  warmed,  carried  to  place  and  fixed  in  position  with 
a  warm  burnisher.  Asbestos  is  used  by  cutting  a  piece  of  the 
paper  to  correct  size,  and  fixing  it  in  position  with  thin  ox5'phos- 
phate  or  chloro-percha. 

Pulp  capping  is  the  term  applied  to  operations  for  the  con- 
servation of  exposed  pulps.  Exposures  are  of  two  kinds,  which 
we  will  term  surgical  and  natural.  Surgical  exposures  are  either 
accidental,  as  when  an  abnormal  shaped  pulp  is  penetrated, 
or  intentional,  as  when  partially  disorganized  dentine  is  removed. 
Natural  exposures  are  those  Avhere  the  pulp  chamber  is  penetrated 
by  decay  before  the  case  comes  under  observation.  In  surgical 
exposures,  inflammation  is  seldom  present,  while  in  natural  ones 
it  usually  is.  It  is  sufficient  for  present  purposes  to  state  that 
pulps  which  are  inflamed  in  any  degree  are  not  promising  sub- 
jects for  pulp,  capping.      If  a  pulp  which  is  exposed  is  to  retain 


70  PULP  PROTECTION. 

its  vitality,  it  must  be  protected  from  irritation  by  pressure,  from 
contact  with  any  irritant,  and  from  therm.al  changes  ;  consequently 
a  material  for  pulp  capping  must  be  one  which  is  nonirritant  to 
pulp  tissue  ;  one  which  can  be  applied  without  pressure,  which 
will  also  protect  the  pulp  from  pressure,  and  one  which  is  a  non- 
conductor. Without  discussing  the  merits  of  the  numerous  methods 
and  materials,  we  will  select  the  two  substances  used  as  pulp  pro- 
tectors, adding  the  oxysulphate  of  zinc,  or  some  of  the  similar 
preparations  in  which  the  oxide  of  zinc  is  combined  with  some 
nonirritant  liquid  to  form  a  mass  which  will  become  sufficiently 
hard  for  the  location  in  which  it  is  to  be  placed.  Where  cavi- 
ties are  so  shallow  that  the  capping  cannot  be  protected  by  a  thin 
layer  of  cement,  from  the  pressure  caused  by  the  insertion  of  a 
metallic  filling,  concave  caps  of  thin  metal  may  be  employed  to 
furnish  this  protection. 

PRACTICAL    EXERCISES. 

These  exrj:ci"es  are  all  upon  teeth  in  the  dummy  articulator. 

PULP    PROTECTION. 

Exercise  1.  In  the  occlusal  surface  of  a  molar,  select  a 
cavity  which  is  sufficiently  deep  „>  allow  of  an '' intermediate. " 
Prepare  and  sterilize;  make  wafer  of  gutta-percha,  pink  base 
plate,  of  the  proper  size  and  thickness;  soften  over  heater  (see 
gutta-percha,  chapter  on  filling  materials)  carry  to  place  with  warm 
burnisher,  carefully  pressing  it  in  position  with  same  instrument. 
The  burnishers  shown  in  Fig.  150  or  151  will  serve. 

Exercise  2.  In  an  incisor  or  bicuspid,  select,  prepare  and 
sterilize  a  cavity  of  class  2  or  3  which  is  too  shallow  to  allow  of  as 
bulky  an  "intermediate  "  as  gutta-percha.  Cut  a  piece  of  asbes- 
tos felt  the  proper  shape  and  size  to  cover  the  axial  wall  of  the 
cavity;  mix  some  oxyphosphate  thin,  coat  one  side  of  the  asbestos 
with  this,  and  carry  it  to  position,  pressing  it  slightly  to  insure  ad- 
hesion. This  exercise  may  be  varied  by  using  chloropercha  in- 
stead of  oxyphosphate. 

PULP    CAPPING. 

Exercise  3.  In  a  bicuspid  or  molar,  select,  prepare  and  steril- 
ize a  deep  cavity  in  which  the  pulp  chamber  is  slightly  pene- 
trated. Cut  a  piece  of  asbestos  felt  of  proper  size  and  shape;  coat 
one  side  with  chloropercha  and  carefully  slide  it  into  position, 
avoiding    any   pressure.      Lightly  press    the   edges    with    a   small 


RADICAL    TREA  7\]/ENT. 


burnisher.     After  allowing  it   to  dry,  insert  an  "  intermediate  "  of 
oxyphosphate,  mixed  thin  enough  to  avoid  pressure. 

Exercise  4.  On  the  mesial  or  distal  surface  of  an  incisor  or 
bicuspid,  select,  prepare  and  sterilize  a  shallow  cavity  in  which  the 
pulp  may  be  readily  exposed.  Strike  up  a  concave  cap  of  thin 
metal,  cutting  it  to  the  proper  size  and  shape  to  cover  fully  the 
point  of  exposure.  Coat  its  concave  surface  with  oxysulphate  of 
zinc,  or  Dickinson's  protector  and  slide  it  into  position.  If  space 
will  permit,  the  cap  may  be  lined  with  gutta-percha  before  apply- 
ing the  oxysulphate.  Where  protective  caps  are  necessarj^  they 
may  be  easily  made  of  vulcanite,  which  is  an  excellent  nonconduct- 
or.    In  these  exercises  other   materials   may  be   employed  at    the 


D  shows  the  oxysulphate.     C  shows  the  metal  or  asbestos  cap.     B  shows 
the  intermediate,  and  A  the  filling. 

option  of    the  teacher;  the  methods  are  much  the  same  for  all  ma- 
terials.     The  chief  point  is  to  az^oid pressure. 

RADICAL    TREATMENT. 

Surgical  devitalization.  While  the  ancient  custom  of  extir- 
pating the  pulp  with  the  actual  cautery  has  been  abandoned,  it  is 
frequently  desirable  to  remove  pulps  without  waiting  for  the 
slower  method  of  devitalizing  with  drugs.  The  fact  that  unin- 
flamed  pulps  are  not  sensitive  at  the  moment  of  their  exposure, 
when  such  exposure  is  sudden,  is  taken  advantage  of  b}'  some  op- 
erators when  preparing  teeth  with  healthy  pulps,  for  porcelain 
crowns.  The  tooth  is  girdled  with  a  share  groove  close  to  the  gin- 
gival border;  is  cut  off  with  excising  forceps,  and  the  pulp  re- 
moved instantly  with  a  barbed  broach  or  by  driving  in  and  immedi- 
ately withdrawing    a  hickory  or  orangewood  point  having  a  long 


72  SURGICAL  REMOVAL  OF  THE  PULP. 

taper.  While  this  method  is  comparatively  painless  and  is  prac- 
ticable for  those  teeth  whose  crowns  are  to  be  replaced  by  porce- 
lain ones,  it  is  not  applicable  to  those  teeth  whose  crowns  are  to 
be  retained  and  filled.  In  rare  instances  pulps  may  be  removed 
surgically,  without  pain,  after  being  freely  exposed,  but  the  irrita- 
tion attendant  upon  the  exposure  of  the  pulp  is  usually  sufficient 
to  awaken  and  increase  the  sensitiveness  of  the  pulp  and  there  is 
no  shock  to  obtund  this  sensitiveness,  as  there  is  in  the  excision  of 
a  tooth. 

In  those  cases  where  the  necessities  of  the  case  or  the  judg- 
ment of  the  operator  indicate  the  surgical  removal  of  a  pulp,  the 
cavity  should  be  deepened  as  much  as  possible  without  pain.  In 
those  cases  where  local  anaesthesia  proves  inefficient,  general  anaes- 
thesia may  be  resorted  to,  or  the  operation  may  be  performed 
during  the  first  or  second  stages  of  anaesthesia  by  ether,  chloro- 
form, or  the  A.  C.  E.  mixture.  Burs,  broaches  and  all  instruments 
should  be  in  readiness  so  that  the  pulp  may  be  exposed  and 
removed  expeditiously.  Thus  far  we  have  considered  only  those 
cases  where  there  was  no  natural  exposure,  or  at  least  those  where 
there  was  no  degree  of  inflammation.  Pulps  which  are  inflamed 
ever  so  slightly  are  too  sensitive  to  permit  of  their  surgical  removal 
without  anaesthesia,  either  local  or  general.  In  many  cases  of 
actual  exposure  the  pulp  may  be  sufficiently  anaesthetized,  by  the 
application  and  injection  of  a  strong  solution  of  cocaine,  to  permit 
of  its  painless  removal.  The  author  has  removed  pulps  painlessly 
by  the  use  of  a  twelve  per  cent  solution  of  cocaine  in  carbolic  acid 
two  per  cent,  causing  the  cocaine  to  act  upon  the  pulp  by  electro- 
lysis. The  method  is  to  place  the  negative  pole  of  the  galvanic 
battery,  which  terminates  in  a  small  pad  moistened  with  saline 
water,  upon  the  gum  over  the  tooth  to  be  operated  upon;  place  in 
the  cavity,  upon  a  pledget  of  cotton  moistened  with  the  cocaine 
solution,  the  positive  pole,  whose  terminal  is  a  platinum  pomt. 
The  current,  a  continuous  one,  should  be  applied  gradually  and  at 
no  time  should  it  be  strong  enough  to  be  unpleasant  to  the 
patient.*  Aside  from  the  lack  of  time  in  which  to  extirpate  a  pulp 
by  the  application  of  drugs,  the  argument  for  surgical  devitaliza- 
tion is  that  it  avoids  the  pain  frequently  present  during  the  action 
of  the  drug,  and  is  less  likely  to  excite  inflammation  in  the  apical 
region.      Surgical  removal  of  the  pulp  should  never  be  attempted 

*This  method  was  published  in  the  Dental  Review,  Vol.  Ill  ,  page  169,  by 
Dr.  D.  F.  McGraw 


DE 1 7  T A  LIZ  A  770  AT  B  V  DR  UGS.  73 

until  direct  access,  as  nearly  on  a  line  with  the  axis  of  the  principal 
canal  as  possible,  is  obtained  and  an  opening  made  into  the  pulp 
chamber  of  sufficient  size  to  permit  of  the  removal  of  the  pulp. 

Devitalization  by  drugs.  The  drugs  used  in  devitalizing  pulps 
are  usually  escharotic.  Those  generally  employed  are  arsenious 
acid,  carbolic  acid,  and  chloride  of  zinc.  Arsenious  acid  is  in  a 
sense  escharotic,  but  it  acts  by  directly  destroying  life;  it  kills  the 
pulp  by  irritation,  increases  the  flow  of  blood  to  the  parts,  enlarges 
the  arteries,  prevents  the  return  of  blood  to  the  veins,  thus  causing 
strangulation.  Carbolic  acid,  like  other  true  escharotics,  acts  by 
combining  with  albumen,  producing  decomposition  of  the  part  and 
forming  an  eschar.  It  is  somewhat  self-limiting  and  requires 
repeated  applications.  Chloride  of  zinc  is  also  a  true  escharotic; 
owing  to  its  great  affinity  for  water  and  its  power  of  combination 
with  albumen,  it  penetrates  deeply.  Man}'  other  agents,  such  as 
dilute  hydrochloric,  nitric  and  chromic  acids  are  sometimes  em- 
ployed, but  they ,  will  not  be  further  considered.  None  of  the 
agents  used  accomplish  the  object  painlessly  without  previous 
treatment  by,  or  combination  with  some  anodyne  or  obtundent. 

As  arsenious  acid,  or  cobalt,  which  contains  arsenic,  are  the 
chief  "  potential  cauterants  "  used  in  devitalizing  pulps,  our  atten- 
tion will  be  confined  to  it.  On  account  of  its  destructive  action 
upon  vital  tissue,  //  must  be  confined  tfi  the  cavity;  if  allowed  to  come 
in  contact  with  the  soft  tissues  surrounding  the  tooth,  it  will  cause 
violent  inflammation,  and  may  result  in  necrosis  of  the  alveolar 
process.  It  should  never  have  a  surp^'.is  of  the  liquid  with  which 
it  is  mixed,  for  the  pressure  of  inserting  whatever  substance  is  used 
to  retain  it  in  the  cavity,  may  squeeze  it  out,  carrying  with  it  suffi- 
cient arsenic  to  do  mischief.  As  the  chief  action  of  arsenic  upon 
inflamed  pulp  tissue  will  be  to  cause  severe  pain,  it  must  not  be 
applied  until  inflammation  is  reduced.  As  deciduous  teeth  and 
permanent  ones  in  the  mouths  of  very  young  persons  have  large 
foramina  it  is  unsafe  to  employ  arsenic  as  a  devitalizing  agent.  It 
is  wiser  to  destroy  such  pulps  by  the  slower  means  of  carbolic  acid 
crystals.  The  length  of  time  that  arsenic  should  remain  in  a 
cavity  is  a  disputed  point.  It  accomplishes  its  purpose  in  from 
three  to  twelve  hours,  depending  upon  the  structure  of  the  teeth, 
the  idiosj'ncrasies  of  the  individual,  and  whether  the  pulp  has  been 
freely  exposed;  hence  there  seems  to  be  nothing  gained  by  leaving 
it  longer  than  twent3'-four  hours.  Again,  should  the  pulp  be 
removed  at  once,  or   should  it  remain  until   the  pulp  is  ready  to 


74  APPLYING  ARSENIC. 

slough?  It  is  claimed  that  because  of  the  penetration  of  the 
tubuli  by  the  processes  of  the  innumerable  odontoblastic  cells  of  the 
pulp,  if  attempts  are  made  to  remove  the  pulp  before  it  is  ready  to 
slough;  that  patches  of  the  membrana  eboris  may  remain.  We 
will  say  that  the  pulp  should  be  removed  before  it  reaches  the  early 
stages  of  putrescence,  and  that  the  success  of  the  subsequent  ope- 
rations depends  much  upon  the  removal  of  all  of  the  pulp. 

As  our  only  object  is  to  give  the  student  sufficient  data  to 
enable  him  to  perform  the  practical  operations  intelligently,  the 
subject  will  not  be  pursued  further.  The  icnowledge  and  judgment 
necessary  to  enable  the  student  to  differentiate  in  his  prognosis, 
cannot  he  obtained  until  he  has  clinical  experience;  hence  the 
teaching  in  the  technic  laboratory  should  be  confined  to  those 
points  which  will  aid  him  in  his  work  there. 

PRACTICAL     EXERCISES. 

Surgical  devitalization.  The  exercises  under  canal  treatment 
have  given  employment  for  the  same  instruments,  and  in  much  the 
same  manner  as  they  are  used  in  surgical  removal  of  the  pulp,  and 
as  the  conditions  found  in  vital  teeth  can  only  be  imagined  in  dried 
ones,  the  practical  instruction  under  this  head  may  be  confined  to 
demonstrations  by  the  teacher. 

DEVITALIZING  BY  DRUGS. 

Exercise  1.  Select  a  cavity  in  which  there  is  exposure  of  the 
pulp;  moisten  J„  grain  of  arsenious  acid  with  oil  of  cloves;  apply 
the  mixture  to  the  concave  surface  of  a  metal  cap,  prepared  as  in 
exercise  4,  pulp  capping,  and  carry  the  cap  to  position  over  the  ex- 
posure. Fill  the  cavity  with  low  grade  gutta-percha.  At  the  next 
meeting  of  the  class,  remove  the  filling  and  cap;  wash  the  cavity 
thoroughly;  apply  tannin  and  glycerine  on  a  small  pledget  of  cot- 
ton; refill  the  cavity  with  gutta-percha,  and  let  it  remain  for  one 
week.  At  the  expiration  of  that  time  remove  the  pulp  and  proceed 
as  in  practical  exercises  under  canal  filling. 

Exercise  2.  In  another  cavity  apply  the  arsenic  and  oil  of 
cloves  on  a  minute  pledget  of  cotton  or  on  a  bit  of  asbestos  paper, 
protecting  it  and  sealing  it  in  the  cavity  with  cotton  moistened  with 
sandarac  varnish.  At  the  next  meeting  of  the  class,  remove  appli- 
cation, extract  the  pulp,  and  fill  at  once.  The  time  is  specified  in 
these  exercises  merely  to  impress  these  things  upon  the  mind  of  the 
student.  He  should  also  be  impressed  with  the  importance  of  ex- 
cluding the  saliva  during  all  these  operations. 


CHAPTER  VI. 


FILLING    MATERIALS. 

Only  such  materials  and  preparations  of  materials  as  are  used 
by  the  student  in  his  primary  work  will  be  considered  ;  dealing 
with  the  elementary  principles  which  govern  the  filling  of  teeth  ; 
treating  each  material  under  the  subdivisions  of  characteristics 
and  composition,  preparation,  introduction  and  finishing. 

Rents,  fissures,  holes  or  cavities  in  any  object  are  best  mended 
with  a  substance  possessing  the  characteristics  of  the  object  itself. 
The  other  factors  which  govern  the  selection  and  application  of  a 
filling  material  are  the  location,  environment  and  use  of  the  object. 

Considered  as  objects  having  holes  or  cavities  to  be  mended 
or  filled,  the  teeth  present  surfaces  having  great  variety  of  form, 
and  resembling  glass  or  porcelain  in  density  and  color.  Exami- 
nation discloses  that  the  object  has  a  covering  or  shell.  That  this 
shell  is  made  up  of  blocks  or  rods  arranged  upon  the  surface  of 
the  tooth  much  as  blocks  are  laid  in  a  pavement;  the  rods  are 
held  together  by  a  cement  substance.  That  when  a  hole  is  once 
made  in  this  shell  the  rods  or  blocks  around  its  border  may,  under 
sufficient  strain,  be  cleaved  or  split  off  in  small  sections. 

Further  examination  shows  that  the  substance  beneath  this 
shell  much  resembles  bone  except  that  it  is  harder  and  more 
dense.  That  the  tooth  substance  when  denuded  of  its  shell  at  anj' 
point  is  sensitive  to  thermal  changes,  and  that  in  its  center  is  a 
cavity  or  chamber  which  contains  an  organ  still  more  sensitive. 
The  thinness  of  the  shell  and  its  liability  to  fracture  indicate  that 
the  filling  for  any  existing  cavity  would  better  be  inserted  in  the 
substance  underlying  the  shell.  This  is  necessary  when  the  cavity 
penetrates  the  substance  of  the  tooth. 

From  our  investigations  of  the  tooth  as  an  object,  we  conclude 
that  its  characteristics  demand  a  filling  material  which  will  present 
a  hard  surface,  highly  polished  or  enameled,  bluish  white  or  yellow- 
ish white  in  color,  and  that  it  must  possess  nonconducting  proper- 
ties, or  be  preceded   by  some  substance  which  is  a  nonconductor. 

As  masticati'ng  apparatus  we  must  consider  the  location  of  the 


76  REQUISITES   OF  FILLING  MATERIALS. 

teeth,  their  environment  and  their  use.  We  find  them  situated  in 
the  oral  cavity,  and  arranged  in  two  rows  bent  in  the  form  of  an 
arch,  vi^ith  the  crown  of  the  arch  presented  to  the  opening  of  the 
cavity.  The  arches  are  hinged  at  their  base  in  such  a  manner  as 
to  permit  the  teeth  to  separate  some  two  and  one-half  inches  at 
the  widest  point.  The  teeth  are  close  together,  and  practically 
immovable  in  their  sockets.  As  cavities  appear  upon  all  surfaces, 
there  are  many  to  which  access  is  difficult.  These  conditions 
demand  that  filling  materials  be  capable  of  introduction  piece- 
meal, or  iti  a  plastic  condition ;  and  to  fulfill  the  requirements 
indicated  under  characteristics,  the  material  must  form  a 
homogeneous  mass  not  subject  to  such  molecular  change  as  would 
affect  its  integrity. 

Further  observation  reveals  the  fact  that  the  cavity  in  which 
the  teeth  are  situated  is  warm  and  moist  and  that  substances  are 
taken  into  it  which  undergo  chemical  change;  that  portions  of  the 
surfaces  of  the  teeth  are  constantly  in  contact  with  the  results  of 
these  changes.  Hence  another  quality  is  demanded  of  a  filling 
material,  the  ability  to  resist  chemical  solution. 

Lastly,  we  observe  that  as  the  two  rows  or  arches  come  in  con- 
tact with  each  other  in  the  act  of  mastication,  the  cutting  or  grind- 
ing surfaces  are  subjected  to  more  or  less  wear.  For  this  reason 
filling  materials  for  cavities  on  these  surfaces  must  have  the  ability 
to  resist  mechanical  abrasion. 

To  summarize,  filling  materials  must  possess  density  and 
hardness,  tenacity,  resistance  to  strain  or  wear,  low  conductivity, 
ease  of  introduction,  freedom  from  chemical  action,  freedom  from 
molecular  change,  capability  of  polish,  and  a  color  which  will  har- 
monize with  or  make  a  pleasant  contrast  to  tooth  color. 

The  materials  to  consider,  are  gold,  amalgam,  tin,  cement, 
and  gutta-percha.  As  much  knowledge  of  gold  and  tin  is  gained 
from  a  study  of  amalgam  alloys,  they  will  be  considered  first. 

Amalgam. — A  combination  of  a  metal  or  an  alloy  with  mer- 
cury, by  the  mercury.  Amalgams  must  be  considered  as  alloys  in 
which  all  or  part  of  the  combination  or  mixture  has  been  accom- 
plished by  the  mercury.  Amalgam  alloys  should  be  composed  of 
such  metals  as  will  form  an  amalgam  having  density,  tenacity, 
good  plasticity,  low  conductivity,  freedom  from  the  action  of  such 
chemical  agents  as  are  found  in  the  oral  cavity,  and  having  such 
fusing  points  and  behavior  in  hardening  as  to  overcome,  in  the 
greatest  degree,  the  spheroidal  tendency  imparted  by  the  mercury. 


AMALGAM.  77 

Alloy. — A  combination  (fusing  together)  of  two  or  more 
metals  by  heat.  "  An  alloy  is  either  (1)  a  solution  of  one  metal  in 
another,  (2)  a  chemical  combination,  (3)  a  mechanical  mixture, 
(4)  or  a  mixture  of  two  or  all  of  the  above."  (Matthiessen.)  So- 
lutions retain  to  a  greater  or  less  extent,  the  properties  of  their 
component  parts  as  do  mechanical  mixtures.  Chemical  com- 
pounds are  generally  formed  in  definite  atomic  proportions,  and 
exhibit  properties  differing  from  either  of  their  components. 
Nearly  all  alloys  belong  either  to  the  3d  or  4th  class  of  Matthies- 
sen. Tenacity  is  usually  higher  in  an  alloy  than  that  of  its  com- 
ponents. Malleability  and  ductility,  are  usually  lessened  in  alloys. 
Conductivity  is  usually  lower  in  alloy  than  that  of  its  components. 

To  give  the  greatest  amount  of  information  in  small  space  the 
following  tables  are  presented,  the  metals  employed  in  amalgam 
alloys  are  arranged  in  the  order  of  their  importance;  under  proper 
heads  are  given  the  properties  or  characteristics  which  may  exert 
an  influence  in  the  resultant  compound.  When  the  relative  rank 
is  given,  the  grading  applies  only  to  the  metals  enumerated  in  their 
relation  to  each  other. 


Mercury 
Silver  . 
Tin  ... 
Copper 
Gold  . . 
Zinc   . . 
Platinum 
Cadmium 
Antimony 
Palladium 


LATIN  TERM. 


Hydrargyrum. 
Argentum  . .  . . 
Stannum. .    . . 

Cuprum 

Aurum 

Zincum 

Platinum 

Cadmium  .  .  . . 

Stibium 

Palladium.  .  .  . 


SYMBOL. 


Hg. 
Ag. 
Sn. 
Cu. 
Au. 
Zn. 
Pt. 
Cd. 
Sb. 
Pd. 


13. 
10. 

7. 

8. 
19, 

7, 
21, 

8, 

6, 
11 


FUSING  PT.   (f.) 


39° 

1873° 

442° 

1996° 

2016° 

773° 
above  3500°* 

442° 

842° 
above  3500° 


EXPANSION. t 


4th  Rank 

3d 

5th 

6th 

2d 

8th 

1st 

7th 

9th 


(*  In  oxyhydrogen  flame.)         (t  When  raised  from  32°  to  212°  F.) 


TENACITY. 

MALLEABILITY. 

DUCTILITY. 

CONDUCTIVITY. 

HEAT. 

ELECTRICITY. 

Mercury  .... 

Silver 

Tin 

Copper  

Gold 

Zinc 

Platinum  .  .  . 
Cadmium  .  . 

8d    rank 
6th     " 
1st     ■■ 
4th     " 
5th     " 
2d      " 
7th     " 
brittle 
2d  rank 

2d    rank 
4th     " 
3d      " 
1st      " 
7th     " 
6th     " 
5th     " 
brittle 
8th  rank 

2d     rank 
7th     " 
4th     " 
1st      " 
Gth     " 
3d      " 
8th     " 
brittle 
5th  rank 

1st  rank 
5th     ■  ■ 
2d      " 
3d      " 
4th     " 
6th      ' 

1st  rank 
5th     " 
2d      " 
3d      ■• 
4th     '■ 
6th     ■' 

Antimony .  .  . 
Palladium.  .  . 

Note. — The  electrjcal  state  of  all  the  metals  except  mercury  is  positive. 


7^  ALLOYS. 

SOLUBILITY. 

Mercury — Soluble  in  dilute  nitric,  and  hot  sulphuric  acid. 
Silver — In  nitric  and  hot,  strong  sulphuric  acid. 
Copper — In  hot  mineral    acids;    slowly  attacked   in    air    and 
moisture  by  vegetable  acids,  alkalies,  and  saline  solutions. 

Gold — In  aqua  regia;  not  affected  by  single  acids  or  alkalies. 
Zinc — In  dilute  acids,  and  solutions  of  the  alkaline  hydrates. 
Platinum — Is  dissolved  slowly  in  aqua  regia. 

OXIDATION    OR    CORROSION. 

Mercury — Not  affected  by  air  or  moisture. 

Silver — Not  acted  upon  by  air  or  water;  but  readily  by  sul- 
phuretted hydrogen. 

Tin — Oxidizes  very  slowl}^ 

Copper — In  moist  air  becomes  coated  with  a  green  carbonate; 
is  tarnished  by  sulphuretted  hydrogen. 

Gold — Unaffected  by  air,  water  or  sulphur. 

Zinc — Tarnishes  slowly;  is  coated  with  carbonate  in  moist  air. 

Platinum — Unaffected  by  air  or  water. 

Cadmium — Tarnishes  slowly  in  air  and  sulphuretted  hydrogen. 

Antimony — Oxidizes  badly  when  amalgamated. 

Palladium — Does  not  oxidize  easily,  but  is  acted  upon  by 
iodine. 

COMBINATION    WITH    MERCURY, 

Silver — Forms  definite  crystalline  chemical  compounds  with 
mercury. 

Tin — Unites  with  mercury  in  atomic  proportions,  forming  a 
weak   crystalline  compound.     (Kirk).      Mitchell  says  it  does  not. 

Copper — Does  not  form  definite  compounds  with  mercury; 
but  in  the  form  of  crystals,  is  dissolved  by  it  in  varying  proportions. 

Gold — Is  dissolved  by  mercury  in  all  proportions;  but  does 
not  form  a  definite  atomic  compound. 

Zinc — Unites  with  mercury  in  atomic  proportions. 

Platinum — Only  unites  with  mercury  when  reduced  to  a 
spongy  condition. 

Palladium — The  union  with  mercury  is  probably  chemical. 

COMBINATION    WITH    OTHER    METALS. 

Mercury — Dissolves  all  metals  but  iron. 

Silver — Has  affinity  for  platinum. 

Tin — Has  affinity  for  gold  and  platinum. 


PROPERTIES  OF  MEl^ALS. 


7!) 


Copper — Unites  with  zinc  in  all  proportions;  and  in  certain 
proportions  forms  definite  compounds. 

Gold — Unites  with  silver  in  any  proportion;  and  is  rendered 
very  brittle  by  the  least  trace  of  antimony,  palladium  or  lead. 

Zinc — Unites  in  all  proportions  with  gold  and  tin;  forms 
chemical  compounds  with  platinum. 

Platinum — Unites  in  definite  proportions  with  silver  and 
cadmium. 

CONSISTENCY.  CRYSTALLIZATION.  * 

Fluid  at  ordinary  Spherical  above 

temperatures.  39°  F. 

Soft  between  Gold  Regular  system. 

and  Copper. 
Soft.  Quadratic  system. 

Soft,    hardens    by  Regular    system, 
hammering. 
Yellow;lustrous.   Soft,  hammering  or    Regular    system, 
burnishing     har- 
dens. 

Bluish  white.         Brittle  unless  heat-  Rhombic  system, 
ed  and  rolled. 

Platinum.     White,     tinged     A  little  softer  than  Practicall}^  amor- 

with  blue.             copper.  phous. 

White,    with          Between  tin  and  Regular     octahe- 

zinc.  drons. 

Hard;   brittle.  Rhombic  system. 

Hard  as  platinum.  Regular    system. 


NAME. 

COLOR. 

Mercury. 

Silver  white, 

lustrous. 

Silver. 

Pure  white, 

lustrous. 

Tin. 

White,  brillia 

Copper. 

Red. 

Gold. 


Zinc. 


Cadmium 

blue  tinge. 
Antimony.  Bluish  white 
Palladium.   White. 


properties  imparted  to  an  alloy  by  the  various  metals. 
Mercury,  being  the  controlling  metal,  imparts  its  spherical 
tendenc}'  to  the  amalgamated  mass;  especially  in  those  alloys 
which  are  -'solutions,"  or  "mechanical  mixtures."  This  tendency 
is  greater  with  those  metals  having  a  low  fusing  point,  cooling 
slowly,  and  when  amalgamated  setting  slowly,  as  tin;  and  less 
with  those  which  melt  at  a  higher  temperature,  cool  quickly,  and 
set  quickly  when  amalgamated,  as  silver  and  copper. 

Silver  controls  hardening  or  setting  because  of  its  crystalline 
form  and  chemical  affinity  for   mercury;  it  maintains  the  bulk  in- 

*"  Regular  crystals  expand  equally  in  all  directions;  rhombic  and  quadratic 
ores  e.xpand  differently  in  different  directions." — Enc.  Brit.,  Vol.  XV' I.,  p.  6^. 


80  INFLUENCE  OF  METALS. 

tegrity  of  the  filling,  and  should  be  the  largest  component  of  an 
alloy.  The  silver  sulphide  formed  by  the  action  of  sulphuretted 
hydrogen  is  supposed  to  have  prophylactic  action  against  decay. 

Tin  should  be  next  in  quantity,  because  it  increases  plasticity, 
prevents  discoloration,  and  reduces  conductivity.  It  also  retards 
setting,  reduces  edge  strength,  and  favors  spheroiding;  hence, 
should  not  be  used  in  such  proportions  as  to  become  the  controll- 
ing metal. 

Copper  diminishes  shrinkage,  hastens  setting,  and  adds  to  the 
present  and  possibly  to  the  permanent  whiteness  of  the  filling.  It 
is  also  supposed  to  have  greater  compatability  with  tooth  sub- 
stance and  pulp  tissue  than  other  metals,  and  has  been  shown  to 
have  antiseptic  action. 

Gold  lessens  shrinkage,  resists  corrosion,  increases  edge 
strength,  increases  smoothness  and  plasticity,  and  hastens  setting; 
all  these  to  a  greater  degree  in  small  quantities  than  any  other 
metal,  5  to  7  per  cent  being  all  that  is  advantageous  to  use. 

Zinc  controls  shrinkage,  hastens  setting,  improves  color,  and 
imparts  a  peculiar  smoothness  in  mixing. 

Platinum — Authorities  differ  in  regard  to  the  influence  of  this 
metal;  some  claiming  that  it  increases  setting,  hardness,  stability, 
and  improves  color;  while  others  contend  that  it  imparts  no  prop- 
erties which  cannot  be  obtained  by  a  judicious  combination  of 
other  metals;  which  seems  to  be  true. 

Cadmium  having  been  proven  to  be  dangerous  to  pulp  vitality, 
should  never  be  used. 

Antimony  blackens  so  badly  that  the  properties  of  controlling 
shrinkage,  and  increasing  plasticity  which  it  imparts,  do  not  seem 
to  be  of  sufficient  advantage  to  warrant  its  employment. 

Palladium  does  not  improve  alloys,  but  amalgamated  alone 
with  mercury,  furnishes  an  amalgam  which  does  not  shrink  or  dis- 
color, but  its  expense  hinders  its  universal  use. 

It  is  an  open  question  whether  freedom  from  discoloration  is  a 
desirable  attribute;  it  is  certainly  true  that  cavity  surfaces  under 
leaky  fillings  which  have  become  coated  with  a  black  oxide  or  sul- 
phide, have  remained  free  from  decay  for  years.  We  hold  that  un- 
sightliness  is  the  principal  objection,  unless  such  chemical  com- 
pounds are  formed  as  will  cause  wasting  of  the  filling  or  prove  detri- 
mental to  the  health  of  the  patient. 

Since  these  tables  were  prepared   aluminum  has  been  intro- 


ALUMINUM.  81 

duced  as  a  constituent  of  amalgam  alloys.  Its  sp.  gr.  is  2.6;  the 
lightest  of  the  metals.  Fusing  point,  1300°F.  Its  tenacity,  in  pro- 
portion to  its  weight,  is  equal  to  steel.  Malleability  next  to  silver. 
Ductility  next  to  copper.  Conductivity  about  the  same  as  copper. 
It  does  not  oxidize  or  corrode  and  prevents  oxidation  when  com- 
bined with  other  metals;  but  only  a  small  per  cent  can  be  com- 
bined in  an  alloy.  It  is  not  readily  acted  upon  by  mercury.  In 
amalgam  alloys  it  is  supposed  to  whiten  them  and  prevent  discol- 
oration. 

An  amalgam  is  produced  by  precipitating  pure  copper,  in  the 
form  of  crystals,  from  a  saturated  solution  of  sulphate  of  copper 
into  mercury,  in  which  form  it  is  capable  of  solution  in  mercury. 
This  precipitation  is  accomplished  by  galvanic  action  or  by  plac- 
ing a  rod  of  iron  in  tlie  solution.  The  galvanic  method  is  preferred 
When  the  solution  has  been  carried  to  the  limit,  the  mass  is  put  in 
a  wedgewood  mortar  and  triturated  thoroughly;  the  surplus  of 
mercury  is  removed  by  squeezing  in  a  chamois  skin  bag.  This 
process  is  repeated,  resorting  to  heat  to  soften  the  mass,  as  it  be- 
comes necessary,  until  amalgamation  is  complete  ;  it  is  then 
moulded  into  small  ingots  and  allowed  to  harden.  As  this  prepa- 
ration possesses  characteristics  peculiarly  its  own  it  will  be  consid- 
ered apart  from  ordinary  amalgams. 

The  qualities  which  commend  amalgams  are  density,  hardness, 
ease  of  introduction,  and  cheapness.  Tiie  objections  to  it  are  its 
color,  or  rather  its  disposition  to  discolor,  a  lack  of  ductility  and 
tenacity — edge  strength — -a  tendency  to  molecular  change  in  harden- 
ing, a  liability  to  chemical  or  electrical  changes  in  the  mouth,  and 
its  conductivity.  Compatibility  with  tooth  substance  and  prophy- 
lactic action  are  disputed  points. 

Density  and  hardness  are  qualities  which  all  amalgams  possess 
to  a  degree  which  enables  fillings  to  withstand  all  strain  and  wear 
to  which  they  are  likely  to  be  subjected,  and  to  receive  a  perfect 
finish. 

Ease  of  introduction,  which  is  probabl}'  its  strongest  recom- 
mendation, is  liable  to  abuse,  as  its  peculiarities  demand  the  great- 
est care  in  its  manipulation.  Cavities  should  be  as  thoroughly 
prepared  for  its  reception  as  for  gold.  It  should  be  as  carefull}'  in- 
troduced, condensed,  and  finished  as  is  gold.  When  this  is  done 
its  other  advantage,  cheapness,  is  greatl}'  modified.  Cheapness 
should  be  the  last  quality  considered.      It  is  better  to  fill  teeth  well 


82  PROPERTIES  OF  AMALGAMS. 

with  amalgam  than  to  allow  them  to  be  lost  because  the  patient 
cannot  afford  gold,  but  ordinarily  the  choice  of  materials  should  be 
based  on  higher  considerations. 

Color,  while  classed  as  an  objection,  is  frequently  an  advan- 
tage; an  oxidation  of  the  surface  having  been  proved  by  clinical  ex- 
perience to  exert  a  prophylactic  action  against  decay. 

Lack  of  that  ductility  or  tenacity  which  results  in  crumbling 
of  the  edge  next  the  margins  of  the  cavity,  is  a  fault  which  can  be 
overcome  in  cases  where  enamel  margins  are  strong  and  cavities 
can  be  shaped  as  in  Fig.  190;  but  where  enamel  margins  are  frail 
or  must  be  shaped  as  in  Fig.  189,  few  amalgams  have  sufficient  te- 
nacity— edge  strength — to  resist  the  force  of  mastication.  It  is 
also  difficult  to  insert  and  finish  amalgam  perfectly  where  the 
enamel  bevel  is  long. 

Liability  to  molecular  change  is  the  objection  most  difficult  to 
overcome.  Reducing  metals  to  a  plastic  condition  by  mercury  is 
somewhat  similar  to  fusing  them  by  heat;  in  either  process,  as 
metals  lose  their  solid  form  the  molecules  change  their  position — 
separate;  coming  together  again  as  the  mass  regains  its  solidity. 
These  are  natural  conditions  over  which  we  have  but  limited  con- 
trol. 

Chemical  and  electrical  changes  are  certain  to  result  when  the 
conditions  of  the  mouth  are  favorable.  A  thorough  knowledge  of 
chemistry  and  the  intelligent  application  of  its  principles,  alone 
can  combat  this  objection. 

Compatibility  and  prophylactic  action  are  qualities  which  de- 
pend almost  entirely  upon  chemical  action;  whether  this  action  ex- 
erts a  good  or  evil  influence  depends  also  upon  the  recognition  and 
careful  observance  of  chemical  laws. 

Conductivity  is  an  objection  which  can  be  overcome  in  most 
cases  by  the  insertion  of  a  nonconducting  "intermediate." 

The  extent  and  manner  in  which  its  weak  points  may  be  over- 
come has  already  been  stated,  except  that  of  molecular  change. 
The  results  of  the  many  experiments  which  have  been  made  seem 
to  indicate  that  the  change  incident  to  crystallization  must  be  re- 
duced to  the  minimum.  First,  the  alloy  must  be  one  which,  when 
amalgamated,  crystallizes  under  the  regular  system;  second,  the 
mass  must  have  a  minimum  of  mercury,  or  it  must  be  introduced 
after  crystallization  has  begun.  After  choosing  an  alloy  in  which 
the  change  from  crystallization  is  small,  the  best  results  are  ob- 


MIXING  AMALGAM.  83 

tained  by  expressing  all  the  mercury  possible,  driving  the  molecules 
into  the  closest  possible  apposition. 

In  mixing,  the  smallest  amount  of  mercury  should  be  used 
which  will  amalgamate  the  alloy;  the  mass  should  be  thoroughly 
mixed  in  a  mortar,  that  the  mercury  may  come  in  contact  with  every 
particle  of  the  alloy;  any  surplus  mercury  may  be  expressed  by 
squeezing  in  chamois  skin  with  strong  flat  nose  pliers.  The  mass 
should  be  introduced  into  the  cavity  in  small  pieces,  and  thoroughly 
condensed  with  instruments  having  convex  faces;  any  surplus  mer- 
cury should  be  taken  up  as  it  appears  on  the  surface;  very  dry 
pieces  should  be  used  in  finishing,  warming  the  instruments  if  nec- 
essary. 

Copper  amalgam  is  prepared  for  use  b}^  slowly  heating  one  of 
the  ingots  in  an  iron  spoon  until  globules  of  mercury  appear  upon 
the  surface,  v/hen  it  is  triturated  in  a  mortar.  The  subsequent 
manipulation  is  similar  to  that  for  other  amalgams.  In  copper 
amalgam  the  tendency  to  molecular  change  is  slight;  thus  one  of 
the  greatest  objections  to  amalgam  is  overcome.  It  has  also  great 
edge  strength.  The  experiments  of  bacteriologists  show  that  it 
has  marked  antiseptic  action.  It  is  easily  manipulated  and  has 
a  bright  silvery  appearance  when  finished.  In  some  mouths  it  turns 
black  and  sometimes  blackens  the  surface  of  all  other  metallic  fill- 
ings in  the  mouth  as  well  as  the  teeth  themselves.  When  it  turns 
black  it  retains  its  bulk  integrity  and  preserves  the  teeth.  When  it 
retains  its  silvery  whiteness  it  wastes  away;  in  some  cases  the  sur- 
face softens  so  much  that  it  can  be  scraped  off  with  the  finger  nail. 
This  uncertain  behavior  has  led  to  its  abandonment  to  a  great  ex- 
tent. The  conclusions  seem  to  be  that  it  is  not  wise  to  emplo}' 
copper  amalgam  where  there  are  other  metallic  fillings,  or  in 
mouths  in  which  there  is  much  chemical  decomposition. 

The  deductions  we  draw  from  this  study  of  amalgam  are,  that 
considered  under  the  requisites  for  a  filling  material,  it  possesses 
sufficient  density  and  tenacity  to  resist  attrition  and  strain,  and 
sufficient  edge  strength  where  enamel  margins  can  be  properly 
prepared;  that  it  transmits  thermal  changes  so  readily  that  an 
''intermediate  "  is  necessary  where  the  tooth  is  sensitive  to  such 
changes;  that  because  of  its  plastic  condition  it  is  very  easy  to 
introduce;  that  it  is  susceptible  to  chemical  changes  to  such 
extent  that  this  tendency  must  not  be  ignored,  in  any  case  where 
the  elements  conducive  to  such  changes  exist;  that  its  tendency 


84  COPPER  AMALGAM— TIN. 

to  molecular  change  must  be  combated  in  every  way  possible; 
that  it  is  capable  of  receiving  the  necessary  finish,  but  that  its 
color  and  tendency  to  discolor  give  results  which  are  neither  har- 
monious, nor  a  pleasant  contrast  to  tooth  color;  hence  it  is  not 
suitable  for  cavities  which  are  exposed  to  view. 

TIN. 

The  qualities  of  tenacity,  ductility,  malleability,  conductivity, 
oxidation  or  corrosion,  color  and  consistency,  have  been  considered 
in  the  tables.  Tin  for  filling  teeth  must  be  pure.  It  is  prepared 
for  dentists'  use  by  beating  or  rolling  it  into  foil,  which  is  put  up  in 
books  of  uniform  size.  The  number  indicates  the  weight  or  thick- 
ness of  a  leaf;  the  numbers  are  2,  4,  6,  8,  10,  30,  60  and  120.  The 
heavier  numbers  only  are  rolled.  For  introduction  into  cavities, 
strips  of  the  foil  are  rolled  in  a  napkin,  twisted  into  ropes  or  folded 
into  ribbons;  cylinders  are  made  by  rolling  the  ribbons  upon  small 
smooth  broaches.  It  is  also  prepared  for  fillings  by  fixing  a  round 
ingot  in  the  lathe  and  turning  off  shavings  for  immediate  use.  It  is 
claimed  that  tin  is  cohesive  when  prepared  in  this  form.  As  tin 
possesses  to  a  limited  degree,  if  at  all,  the  property  of  cohesion,  or 
welding  without  heat,  its  homogeneity  depends  upon  wedging  or 
interdigitation.  On  this  account  it  can  only  be  employed  in  cavi- 
ties of  class  ],  or  of  division  A,  class  2,  and  in  those  cavities  of 
division  A,  class  3,  where  the  marginal  ridge  is  not  involved,  /.  e., 
cavities  must  have  continuous  walls. 

Density  and  hardness.  Considered  under  the  demands  for  a 
filling  material  we  find  that  tin  fulfills  the  first  requisite,  density,  to 
only  a  limited  extent,  and  it  is  not  sufficiently  hard  to  withstand 
the  wear  of  mastication. 

Tenacity  is  lacking  to  a  degree  which  precludes  its  use  in 
those  cavities  where  restoration  of  contour  is  demanded  and  it  can- 
not be  used  in  cavities  having  such  enamel  bevel  as  is  shown  in 
Fig.  189. 

Low  conductivity.  Platinum  excepted,  tin  is  the  poorest 
conductor  of  the  metals  employed  for  fillings.  For  this  reason  it 
may  be  used  in  those  cavities  which  are  so  sensitive  to  thermal 
changes  as  to  render  the  use  of  gold  or  amalgam  unwise. 

Ease  of  introduction.  With  proper  instruments,  a  proper 
preparation  of  both  the  cavity  and  the  material,  tin  may  be  intro- 
duced with  much  facility  into  such  cavities  as  are  easy  of  access. 

Freedom  from  chemical  action.     While  tin  corrodes  slightly, 


PROPERTIES  OF  TIN.  85 

and  in  some  mouths  considerably,  it  is   not  readily  acted  upon  by 
the  fluids  of  the  mouth. 

Freedom  from  molecular  change.  As  the  crystallization  of 
tin  is  not  interfered  with  in  its  introduction,  there  is  no  subsequent 
change  in  its  bulk  integrity- 
Capability  of  polish.  While  a  tin  filling  may  be  given  a  highly 
burnished  surface,  it  does  not  retain  it,  because  of  the  softness  of 
the  material. 

Owing  to  its  inherent  qualities,  tin  is  somewhat  limited  in  its 
application.  Its  use  is  not  indicated  for  large  cavities  on  occlusal 
surfaces  which  are  subjected  to  much  wear.  Its  use  is  not  in- 
dicated in  those  cases  where  lost  contour  must  be  restored,  or  for 
proximate  fillings  where  its  surface  might  be  roughened  or  dis- 
turbed by  efforts  at  cleansing  with  toothpicks.  It  may  be  used  to 
advantage  in  children's  teeth  and  in  all  cases  where  the  use  of  gold 
is  not  indicated  or  where  it  is  undesirable  to  use  amalgam. 


Cavities  must  be  formed  for  its  reception  as  is  shown  in  Fig 
190^,  a.  a.,  with  no  more  enamel  bevel  than  is  absolutely  necessary 
for  its  protection. 

Plugger  points  for  the  insertion  of  tin  should  be  wedge 
shaped,  with  sharp  and  deep  serrations.  When  the  wedging  is 
complete,  the  surface  may  be  condensed  with  convex  faced  foot 
pluggers  having  smoother  and  shallower  serrations.  Finally  the 
filling  may  be  burnished,  the  surplus  trimmed  off  with  sharp  in- 
struments, and  again  burnished.  Tin  fillings  may  also  be  finished 
with  files,  emery  or  sandpaper  disks  and  strips  of  increasing  fine- 
ness until  the  proper  polish  is  obtained.  Fig.  231  shows  the  man- 
ner of  placing  and  condensing  cylinders  in  the  cavity.  Each 
cylinder  is  condensed  against  those  which  have  preceded  it;  the 


INSERTING   TIN. 


operation  is  continued  until  only  a  small  space  is  left  in  the  center; 
this  space  is  filled  by  wedging  small  cylinders  into  it. 

Fig.  232  shows  the  manner  of  inserting  a  rope  or  ribbon  by 
doubling  it  upon  itself.  In  the  insertion  of  either  preparation  of 
tin,  the  filling  is  arranged  in  concentric  layers;  is  solidified  by 
crowding  each  layer  against  those  which  have  preceded  it,  always 
exerting  the  force  toward  the  walls  of  the  cavity.  The  cylinders  or 
folds  should  project  above  the  walls  of  the  cavity  sufficiently  to 
permit  of  condensing  and  finishing. 

GOLD, 

The  tables  show  that  gold  possesses  tenacity,  malleability, 
ductility,  and  conductivity  in  a  marked  degree;  that  it  does  not 


Fig.  232, 

oxidize  or  corrode;  that  while  it  is  a  soft  metal,  it  becomes  hard  by 
hammering,  rolling,  or  burnishing;  and  that  its  color  contrasts 
more  agreeably  with  the  color  of  the  tooth  than  does  any  other  of 
the  filling  materials. 

Density  and  hardness.  Gold  is  sufficiently  hard  and  dense  to 
enable  it  to  withstand  the  wear  to  which  it  is  subjected. 

Tenacity,  resistance  to  strain.  These  qualities,  together  with 
malleability  and  ductility,  are  possessed  by  gold  to  such  an  extent 
that  it  not  only  resists  strain  when  employed  to  restore  lost  con- 
tour, but  it  is  possible  to  use  it  where  the  enamel  bevel  is  neces- 
sarily long;  a  combination  of  qualities  possessed  by  no  other  ma- 
terial used  for  filling  teeth. 

Low  conductivity.  Gold  is  the  best  conductor  of  the  filling 
materials,  consequently  it  oftener  demands  a  nonconducting  "in- 
termediate." 


PROPERTIES  OF   GOLD.  87 

Ease  of  introduction.  It  is  generally  conceded  that  gold  is 
the  most  difficult  material  to  manipulate,  yet  when  its  qualities  are 
thoroughly  understood,  it  responds  readily  to  careful  and  intelligent 
effort. 

Freedom  from  chemical  action.  It  is  not  affected  by  any 
chemical  action  present  in  the  mouth. 

Freedom  from  molecular  change.  There  is  no  change  in  the 
integrity  of  a  gold  filling  after  its  proper  condensation. 

Capability  of  polish.  Gold  is  capable  of  receiving  either  a 
burnished  or  a  polished  surface. 

Good  color.  It  is  not  harmonious  in  color  with  the  teeth,  but 
its  peculiar  yellow  color  forms  a  pleasant  contrast. 

In  addition  to  these  qualities  it  possesses  the  property  of 
cohesiveness.  Its  freedom  from  oxidation  makes  it  possible  to 
unite  separate  pieces  of  gold  by  pressure  without  the  aid  of  heat; 
heat  is  used  only  for  the  purpose  of  burning  off  impurities  and 
softening  the  gold. 

From  the  foregoing  it  appears  that  the  popularity  of  gold  as  a 
fyiing  material  is  based  upon  the  fact  that  it  fulfills  more  of  the 
requirements  for  a  filling  material  than  any  other  substance 
employed. 

Gold  for  use  in  filling  teeth  must  be  as  nearly  chemically  pure 
as  it  is  possible  to  make  it.  The  greater  amount  comes  to  us  in 
the  form  of  foil,  or  cylinders  and  blocks  made  from  foil.  There 
are  several  other  preparations  produced  by  reducing  gold  to  its 
crystalline  state,  under  various  processes  and  bearing  various 
names,  as  crystal,  sponge,  crystal  mat,  etc.  Only  foil  and  the  vari- 
ous forms  in  which  it  is  prepared  for  use  will  be  noticed. 

Gold  foil  is  prepared  by  beating  or  rolling  (rolling  for  the 
heavier  numbers  only),  and  is  put  up  and  numbered  in  the  same 
way  as  tin  foil.  Unlike  tin,  gold  foil  is  supplied  in  several  grades 
— one,  in  which  the  natural  cohesive  quality  of  gold  has  been  de- 
stroyed by  some  process;  this  is  known  as  noncohesive.  Another, 
in  which  this  property  of  cohesion  is  destroyed  only  in  part — this 
is  known  as  semicohesive.  The  other  form  is  that  in  which  the 
cohesive  property  is  retained  to  its  fullest  extent;  this  is  known  as 
cohesive,  or  extra  cohesive.  Manufacturers  mark  their  products 
as  "soft,"  "semicohesive"  and  "cohesive"  or  "extra  cohesive." 
The  term  "soft"  is  a  misleading  one.  Softness  is  not  synonymous 
with  noncohesiveness.      All   of  the  grades  ma}'  be,  and  are,  under 


88  GOLD  FOIL. 

the  best  processes  of  manufacture,  soft;  this  is  a  natural  property 
of  gold  before  the  particles  are  driven  into  closer  contact  by  con- 
densation. Gold  which  has  been  made  hard  by  condensation  may 
again  become  soft  by  heating  to  redness.  This  is  independent  of 
the  cohesive  property.  Pellets,  blocks,  or  cylinders  of  gold  in  which 
the  cohesive  quality  has  not  been  destroyed,  become  hard  more 
quickly  under  manipulation  than  do  those  which  have  been  made 
noncohesiye;  this  is  because  the  particles  of  cohesive  gold  stick 
together  at  all  points  where  two  surfaces  come  in  contact,  while 
the  surfaces  of  noncohesive  gold  slip  or  slide  upon  each  other. 

The  fullest  exhibition  of  the  cohesive  property  depends  upon 
the  absolute  cleanliness  of  the  surfaces.  Moisture,  fatty  matter,  or 
gases,  especially  sulphuretted  gases,  modify  or  completely  de- 
stroy cohesion.  To  insure  the  absence  of  any  or  all  of  these,  the 
gold  is  heated  to  redness  over  a  flame  in  which  combustion  is  com- 
plete. This  is  called  annealing;  its  purpose  is  two-fold;  first,  to 
cleanse  the  surfaces;  second,  to  secure  the  fullest  degree  of  soft- 
ness. If  there  is  any  doubt  of  the  perfect  combustion  in  a  flame, 
the  gold  may  be  heated  in  a  mica  tray. 

The  principles  governing  the  introduction  of  noncohesive  gold 
are  the  same  as  those  governing  the  introduction  of  tin.  Because  of 
the  hardness  which  is  possible  in  a  noncohesive  gold  filling,  the 
range  of  cavities  where  it  may  be  employed  is  much  greater  than 
for  tin.  As  has  been  stated,  the  amount  of  inherent  strength  neces- 
sary to  the  filling  in  any  given  cavity  is  equivalent  to  the  amount 
of  strain  to  which  the  filling  is  subjected;  this  governs  the  amount 
of  cohesiveness  necessary  in  the  gold  for  any  given  cavity.  Those 
cavities  where  lost  contour  must  be  restored,  usually  require  the 
full  extent  of  the  cohesive  property.  Where  density  of  surface  is 
required  and  the  mass  of  the  filling  is  subjected  to  little  strain,  a 
noncohesive  filling  may  be  faced  with  cohesive  gold.  This  is  ac- 
complished by  mechanical  union  between  the  noncohesive  and  the 
cohesive — i.  e.  a  layer  of  cohesive  foil  is  interdigitated  with  the 
noncohesive  mass.  This  method  is  applicable  to  cavities  of  class 
3,  whose  axial  depth  is  great.  These  cavities  when  prepared  as  in 
Fig.  226,  have  retaining  shape  throughout  their  whole  depth.  The 
cohesive  gold  need  only  be  employed  to  a  depth  necessary  to  allow 
of  a  sufficient  mass  of  cohesive  gold  to  be  retained  in  the  cavity, 
and  to  resist  the  strain  brought  upon  it.  This  is  illustrated  in  Fig. 
233. 


NONCOHESIVE    GOLD. 


89 


The  advantages  of  noncohesive  gold  are  that  it  is  more  readily 
adapted  to  the  walls  of  the  cavit}^,  and  it  can  be  introduced  in 
larger  pieces  and  be  perfectly  condensed  in  a  much  shorter  time,  thus 
saving  fatigue  to  both  patient  and  operator.  The  same  instru- 
ments for  wedging,  condensing,  and  finishing  are  employed  for 
noncohesive  gold  as  for  tin.  The  instruments  for  cohesive  gold 
should  have  fine  shallow  serrations  and  possess  such  points  as  are 
shown  in  Figs.  130  to  146.  Owing  to  the  tendency  of  the  surfaces 
of  cohesive  gold  to  stick  together,  force  should  be  exerted  in  such 


Fig.  333. 


direction,  and  instruments  employed  having  such  faces  as  will 
insure  the  perfect  adaptation  of  each  layer  to  the  walls  of  the  cavity. 

Gold  foil  is  prepared  for  insertion  into  cavities  in  the  same 
forms  as  tin.  Where  the  cohesive  property  is  retained,  the  indi- 
vidual pellets,  ribbons,  blocks,  cylinders,  or  mats  should  be  of 
looser  structure,  also  flatter  and  smaller  than  for  noncohesive  gold 
or  tin.  Cohesive  gold  fillings  are  made  by  uniting  the  separate 
pieces,  la5'er  upon  layer,  thoroughly  condensing  each  layer  before 
another  is  added. 

The  only  combination  with  other  metals  to  be  noticed  is  gold 
and  tin.     The  two  foils  are  combined  in  blocks  or  cylinders  so  that 


90  ZINC  PLASTICS. 

the  layers  of  gold  and  tin  will  alternate;  the  tin  should  never  pre- 
dominate. This  combination  is  useful  at  the  cervical  third  of  large 
cavities  of  Class  3. 

Zinc  Plastics. 

r\^  ^v,!^.-;^^  ^t  TX^r.       S  Powder,  calcined  oxide  of  zinc. 
Oxychlonae  01  Zmc      i  r  •      -j    j  i-  j    ui      j      r     • 

•'  (  J_iquid,  deliquesced  chloride  of  zinc. 

r\        u       u   i      f  '7-        \  Powder,  recalcined  oxide  of  zinc. 
Oxyphosphate  of  Zinc  i  r  •       j  V,  ,■  j    i     •  i     u       i.     •        -j 

^  ^       ^  {  Liquid,  deliquesced  glacial  phosphoric  acid. 

Oxyphosphate  of  Zinc, — with  gelatinized  liquid  for  capping. 

I  Powder,  calcined  oxide  and  calcined  sulphate  of  zinc. 
Oxysulphate  of  Zinc       -|  Liquid,  gum  arable  and  sulphite  of  lime  dissolved  in 
(  distilled  water. 

T-.-  I,-   ^ 'o  r^^^\^r,       \  Powder,  oxide  of  zinc  and  iodoform. 

Dickinson  s  Capping      i  t  •       j    u       u        j  .         j  ^ 

^^    °       /  Liquid,  beechwood  creasote  and  eugenol. 

As  none  of  these  preparations  can  be  considered  as  permanent 
filling  materials,  their  response  to  the  requirements  of  a  filling 
material  will  be  summed  up  as  follows.  They  have  sufficient  den- 
sity and  hardness,  have  low  conductivity,  are  easy  to  introduce,  do 
not  change  in  bulk  integrity,  and  have  good  color.  They  lack  in 
tenacity,  resistance  to  strain  or  wear,  receive  only  an  indifferent 
polish  and  are  soluble  in  the  fluids  of  the  mouth. 

Oxychloride.  As  this  preparation  has  been  proved  to  be  so 
temporary  in  its  nature,  it  is  used  only  where  its  peculiar  power  to 
prevent  decomposition  of  devitalized  tissue  is  desirable;  as  for  fill- 
ing root  canals  in  which  the  pulps  were  putrescent,  or  as  a  lining 
or  temporary  filling,  where  its  ability  to  obtund  sensitive  dentine 
by  destroying  the  terminals  of  the  fibrillae,  make  it  advantageous. 
Its  combination  is  a  chemical  union,  and  it  should  be  thoroughly 
mixed  upon  a  glass  slab,  to  the  consistency  of  cream  for  canal  fill- 
ings, and  to  a  putty  like  mass  for  linings  and  temporary  fillings. 
As  it  is  white  in  color  it  is  useful  as  a  lining  in  teeth  which  have 
been  bleached,  or  in  large  cavities  where  the  gold  or  other  filling 
material  will  show  through  the  enamel  if  some  lining  material  is 
not  employed. 

Oxyphosphate  of  zinc  is  harder,  better  resists  wear,  and  is 
less  irritant  to  vital  tissues.  It  is,  however,  soluble  in  certain 
fluids  of  the  mouth,  notably  in  the  mucous  secretions.  Its  union 
is  a  chemical  one,  but  it  does  not  unite  so  readily  as  oxychloride; 
the   powder  should  be  added  to  the  liquid  in  small  amounts,  thor- 


OXYPHOSPHATE  OF  ZINC.  91 

oughly  spatulating  or  kneading  the  mass,  with  force.  It  should 
be  mixed  to  a  patty-hke  mass,  unless  it  is  to  be  introduced  without 
pressure,  as  when  it  is  used  as  an  "intermediate  "  over  a  pulp  cap- 
ping, when  it  must  be  of  the  consistency  of  cream.  There  are 
many  preparations  of  varying  excellence;  the  best  results  seem  to 
be  obtained  from  those  in  which  the  powder  is  finely  pulverized,  is 
heavy,  and  breaks  apart,  falling  in  masses,  as  the  bottle  is  revolved, 
and  those  in  which  the  liquid  is  thick  and  syrupy  in  appearance 
and  sticky  in  feeling.  Samples  possessing  these  characteristics,  and 
which  mix  unwillingly  but  make  a  fine  smooth  mass,  so  sticky  that 
it  is  removed  from  the  slab  and  spatula  with  difficulty,  and  losing  this 
stickiness  if  rolled  a  little  in  the  fingers,  rebounding  with  a  metal- 
lic ring  when  a  pellet  of  it  is  dropped  upon  any  hard  surface,  and 
breaking  with  difficulty  after  fifteen  minutes,  showing  a  clean  frac- 
ture, generally  wear  well  if  they  are  carefully  introduced  and  fin- 
ished, and  the  moisture  is  excluded  until  the  mass  is  hard. 

Oxyphosphate  with  gelatinized  fluid,  oxysulphate  of  zinc  and 
Dickinson's  material,  are  not  filling  materials,  but  are  intended  as 
nonirritant,  antiseptic  pulp  protectors  or  cappings.  They  are  use- 
ful in  all  cases  of  exposure  or  where  a  thin  laj^er  of  semidecalcified 
dentine  remains  over  the  pulp.  They  are  used  in  conjunction  with 
asbestos  paper  or  a  metal  cap. 

GUTTA-PERCHA. 

This  product  of  the  gutta  perch  tree  is  too  tough  and  unyield- 
ing in  its  natural  state,  to  be  utilized  as  a  filling  material.  For 
dental  use,  oxide  of  zinc  or  some  earthy  matter  is  incorporated 
with  it.  It  comes  to  us  in  two  forms,  pink,  which  is  used  for  base 
plates,  and  white,  the  white  in  several  grades.  It  has  sufficient 
density,  tenacity  and  strength  for  ordinary  purposes  but  not  suf- 
ficient to  resist  the  strain  and  wear  of  mastication.  It  is  an  abso- 
lute nonconductor.  It  is  easy  to  introduce.  While  it  is  free  from 
chemical  action,  it  becomes  soaked  and  rotten  after  long  exposure 
to  the  oral  fluids.  Being  introduced  warm,  it  shrinks  in  cooling. 
Although  incapable  of  polish,  the  so  called  white  varieties  harmo- 
nize well  with  tooth  color.  Its  characteristics  make  it  one  of  the 
best  "intermediates,"  as  well  as  one  of  the  best  canal  filling  ma- 
terials, where  too  much  bulk  is  not  required,  but  precludes  its  use 
as  a  permanent  filling,  except  in  cavities  upon  buccal  surfaces  of 
molars  and  bicuspids.      It  is  also  very  useful   in    deciduous   teeth. 


92  GUTTA-PERCHA. 

The  white  gutta-perchas  are  prepared  in  three  grades,  "  lov/  heat,'' 
"  medium,"  and  "  high  heat."  The  degree  of  heat  necessary  to 
soften  it  depends  upon  the  amount  of  oxide  or  other  substance 
which  it  contains.      The  several  grades  soften  as  follows: 

"Low  heat"  softens  at  from  140.°  to  200. °F. 
Pink,  base  plate  "  "  "  150.°  "  180.°F. 
"Medium"  "         "     "     200.°     "    210.  °F. 

"High  heat"         "         '•'     "     216.°      "    230. °F.* 

All  those  which  soften  below  the  boiling  point  should  be  soft- 
ened over  boiling  water;  the  "  high  "  grade  must  be  softened  on  a 
glass  or  porcelain  slab  over  a  flame.  None  of  the  preparations 
should  be  softened  in  direct  contact  with  the  flame,  because  of  the 
danger  of  burning. 

Warm  instruments  should  be  used  in  its  manipulation.  The 
"  medium  "  preparations  seem  to  give  the  best  results.  The  pink 
base  plate  makes  the  best  points  for  canal  filling.  The  chloro- 
percha  which  is  used  in  pulp  capping  and  canal  filling  is  prepared 
by  dissolving  small  shavings  of  pink  base  plate  in  chloroform.  It 
has  been  suggested  that  iodoform  or  some  antiseptic  be  added 
to  the  solution,  but  as  any  such  substance  would  be  so  firmly  fixed 
against  solution,  its  efficacy  seems  doubtful. 

Practical  Exercises. 

Before  students  begin  their  practical  exercises  the  teacher 
should  demonstrate  each  operation.  The  cavities,  which  were  pre- 
pared in  the  large  clay  models  with  enlarged  copies  in  brass  of  the 
instruments  which  the  students  used  in  cavity  preparation,  may  now 
be  filled;  use  enlarged  pluggers  of  brass,  with  colored  cotton  rolls 
to  represent  cylinders  of  tin  or  gold,  and  ropes  and  ribbons  of  sheet 
wadding  (cotton)  to  represent  ropes  and  ribbons  of  tin  or  gold,f 
soft  clay  of  another  color,  or  putty  may  be  used  to  demonstrate  the 
use  of  plastics. 

A  little  ingenuity  will  enable  the  teacher  to  vary  the  exercises 
to  hold  the  interest  of  the  students  and  to  prevent  the  work  becom- 
ing irksome. 

The  author  is  now  able  to  present  an  illustration  of  a  "rubber 
tooth  form  for  use  in  operative  technics,"  Fig.  234,  which  will  take 

*Flagg, 

•j-This  was  suggested  by  Dr.  D.  M.  Cattell 


PR  A  C  TICAL  EXER  CISES. 


93 


the  place  of  the  toothbrush  handle;  the  bottom  of  the  base  is  slight- 
ly convex  in  order  that  the  cavities  shown  in  Fig.  187  may  be  made 
in  it.  The  teeth  are  typical  forms  thus  giving  opportunity  for  the 
formation  of  typical  cavities.  The  material  is  much  easier  to  cut 
than  dentine  or  bone,  but  dense  enough  to  give  good  margins. 
Another  advantage  is  that  the  character  of  the  material  demands 
sharp,  keen  edged  instruments.  The  teeth  are  placed  far  enough 
apart  to  permit  of  easy  access  to  all  surfaces,  consequently  the  stu- 
dent will  gain  practice  in  contour  iov  forfii  only.  Practice  in  con- 
tour for  contact  and  the  preservation  of  the  interproximate  space 
must  be  gained  by  filling  cavities  (with  plastics)  in  teeth  in  the 
dummy  articulator. 


Fig.  234, 


The  three  points  of  contour,  contact,  and  occlusion  should  be 
carefully  studied,  taking  as  a  basis  a  thorough  recitation  and  drill 
of  pages  130  to  153  of  Black's  Dental  Anatomy,  supplemented  by 
the  arrangement  of  the  teeth  in  the  dummy  articulator,  and  by  the 
study  of  models. 

Exercise  1.  Gutta-percha.  The  teacher  selects  several  cavities 
in  the  teeth  in  the  dummy  articulator  which  the  student  fills  with 
gutta-percha,  pink  base  plate.  One  cavity  is  filled  with  a  pellet  of 
sufficient  size  to  fill  the  cavity,  which  is  softened  over  boiling  water 
or  on  a  Flagg's  gutta-percha  warmer.  It  is  then  inserted  in  the 
cavity  with  warm  instruments,  the  surplus  is  removed  and  the  sur- 


94  PRACTICAL  EXERCISES. 

face  finished  with  warm  burnishers.  Another  cavity  is  filled  with 
smaller  pellets,  softened  as  before,  using  cold  instruments,  trim- 
ming off  the  surplus  with  sharp  trimmers  after  the  mass  has  hard- 
ened. The  surface  may  then  be  finished  with  a  pad  of  cotton  or 
spunk  wet  with  chloroform. 

It  is  presumed  that  the  student  has  already  had  some  expe- 
rience in  handling  gutta-percha  in  his  pulp  protection,  and  canal 
filling  exercises;  but  the  teacher  should  require  such  further  exer- 
cises as  will  thoroughly  familiarize  the  student  with  the  different 
grades  of  this  valuable  material. 

Exercise  2.  Oxychloride  of  zinc.  After  some  preliminary  ex- 
ercise in  mixing  this  cement,  the  student  is  required  to  insert  some 
in  large  cavities  as  a  cavity  lining;  to  insert  one  filling,  keeping  it 
dry  until  the  mass  is  perfectly  set  or  hard,  also  one  which  he  may 
bring  in  contact  with  saliva  before  it  is  thoroughly  set;  this  is  done 
that  he  may  note  the  different  results.  Finish  with  lancet  trim- 
mers and  sandpaper  strips. 

Exercise  3.  Oxyphosphate  of  zinc.  The  preliminary  exer- 
cise should  be  thorough  instruction  and  practice  in  mixing  this 
cement,  making  tests  of  the  various  mixes.  Several  varieties 
should  be  presented.  Then  a  number  of  the  partially  prepared 
cavities  in  teeth  in  the  dummy  articulator  should  be  filled  to 
restore  contour  and  contact.  Fillings  in  cavities  involving  the 
proximate  surfaces  of  bicuspids  and  molars  should  be  inserted 
with  the  aid  of  Dunn's  hand  matrix.  Some  of  the  fillings  should 
be  protected  from  moisture  until  perfectly  hard,  others  should  be 
brought  in  contact  with  saliva  while  they  are  hardening,  the  stu- 
dent taking  careful  notes  of  the  results  in  each  case.  Finish  the 
same  as  oxychloride.  Students  should  be  allowed  all  the  oppor- 
tunity possible  to  become  familiar  with  the  peculiarities  and  pos- 
sibilities of  this  material.  If  possible,  the  teacher  with  the  assist- 
ance of  the  class  should  make  a  batch  of  oxyphosphate. 

Exercise  4.  Amalgam.  Students  will  be  much  benefited  if 
they  are  allowed  to  assist  in  the  manufacture  of  an  amalgam  alloy 
and  of  copper  amalgam.  Whether  this  is  practicable  or  not,  they 
should  mix  amalgam,  both  soft  and  dry,  and  test  the  mixes  by 
inserting  them  in  glass  tubes  which  are  subsequently  immersed  in 
aniline  dye.  One  cavity  should  be  filled  with  a  soft  mix  and  one 
with  a  dry  mix,  which  should  be  allowed  to  harden  before  the  fill- 
ing is  finished.     One  cavity  should  be  filled  with   a  soft  mix  and 


FKAC71CAL  EXERCISES.  95 

one  with  a  dry  mix  which  should  be  wafered  and  finished  at  once. 
Watering  is  the  expression  of  all  surplus  mercury  before  the  mass 
is  inserted  in  the  cavity.  Careful  notes  should  be  taken  of  the 
results  under  the  different  manipulation.  The  partially  prepared 
cavities  in  the  teeth  of  the  dummy  will  give  ample  practice  in  the 
inserting;  contouring,  and  finishing  of  amalgam.  All  amalgam  fill- 
ings must  be  carefully  finished  after  they  are  thoroughly  hard, 
with  finishing  strips  and  discs  of  increasing  fineness-. 

Exercise  5.  Making  ropes  of  tin  foil.  Cut  a  leaf  of  No.  4  tin 
foil  into  three  strips;  roll  each  strip  in  a  clean  folded  napkin;  then 
grasping  the  ends  with  the  thumb  and  index  finger  of  each  hand, 
twist  into  a  rope,  tight  or  loose  as  is  desired.  This  preparation  is 
applicable  for  gold  also,  except  that  for  cohesive  foil  the  roll  should 
not  be  twisted.  Cohesive  gold  should  never  be  touched  by  the 
fingers. 

Exercise  6.  Making  ribbons  of  tin  foil.  Cut  the  leaves  of  No. 
4  foil  as  for  ropes;  with  a  paper  folder  fold  each  strip  lengthwise 
to  the  desired  width.  This  is  the  best  form  of  preparation  for 
cohesive  gold  foil. 

Exercise  7.  Making  cylinders  of  tin  foil.  Prepare  ribbons  of 
the  width  desired  for  the  length  of  the  cylinders.  Roll  each  ribbon 
on  a  small,  square,  smooth  broach,  holding  it  tight  between  the 
thumb  and  finger;  the  size  of  the  cylinders  is  governed  by  the 
length  of  the  ribbon.  This  form  of  cylinder  is  applicable  only  for 
tin  and  noncohesive  gold. 

Exercise  8.  Tin  fillings  of  ropes  or  ribbons.  In  cavity  C,  Fig. 
187,  insert  a  rope  of  tin  as  shown  in  Fig.  282,  beginning  at  one 
end,  pressing  or  crowding  each  fold  against  those  which  have  pre- 
ceded it.  In  folding  the  ropes  or  ribbons,  be  sure  to  leave  suffi- 
cient amount  protruding  from  the  cavity  to  permit  of  condensing 
and  finishing.  When  enough  has  been  introduced  into  one  end  to 
insure  the  wedging  of  the  mass,  fill  the  other  end  in  the  same  man- 
ner. As  the  two  masses  approach  each  other,  that  portion  next 
the  walls  of  the  cavity  should  be  in  advance  of  the  rest;  in  this 
way  a  small  opening  will  be  left  in  the  center  of  the  filling.  After 
the  mass  has  been  thoroughly  condensed  laterally  by  the  use  of 
wedge-shaped  instruments  in  this  central  opening  it  may  be  filled 
with  smaller  ropes.  Instruments  used  in  this  exercise  should  be 
shaped  as  in  Figs.  121,  122,  123  and  124.  After  the  cavity  is 
wedged  full  the  surface  should  be  thoroughly  condensed  with  foot 


96  PRACTICAL  EXERCISES. 

instruments  having  convex  faces,  as  in  Figs.  135  and  136.  This 
exercise  should  be  by  hand  pressure  only.  The  surplus  may  be 
trimmed  off  with  files  and  the  surface  finished  with  sandpaper  or 
emery  paper  strips  of  increasing  fineness,  using  chalk  or  whiting 
and  rouge  on  a  chamois  skin  strip,  to  polish;  or  the  surplus  may  be 
trimmed  off  with  sharp  lancet  trimmers  and  the  surface  burnished. 

Exercise  9.  Tin  filhngs  of  cylinders.  In  cavity  d,  Fig.  187, 
place  a  row  of  large  cylinders  around  the  circumference  of  the 
cavity,  next  the  wall,  as  shown  in  Fig.  231,  flattening  them  against 
the  wall.  Continue  placing  cylinders  in  concentric  layers,  crowd- 
ing each  row  against  those  which  have  preceded,  until  only  a  small 
opening  is  left  in  the  center.  This  opening  may  be  filled  with  a 
conical  cylinder,  or  with  a  rope,  as  in  Exercise  8.  After  the  cavity 
is  full  the  surface  must  be  condensed  as  in  Exercise  8.  The  same 
instruments  are  used  as  before.  The  remaining  cavities,  a,  b  and 
e,  may  be  filled,  using  ropes,  ribbons,  or  cylinders  of  heavier  foil, 
as  the  teacher  may  direct.  One  or  more  cavities  may  be  filled 
with  shavings  of  tin,  prepared  as  described  on  page  83.  A  com- 
pound or  double  dovetailed  cavity  resembling  Fig.  226,  should  be 
prepared  in  either  end  of  the  toothbrush  handle  or  in  the  base  of 
the  rubber  tooth  form,  which  involves  the  surface  and  the  end. 
One  of  these  cavities  should  be  filled  with  ropes  of  tin  foil,  the 
other  with  tin  and  gold  ropes  or  cylinders  for  the  basal  two- thirds 
of  the  cavity,  filling  the  remaining  third  with  gold.  As  noncohesive 
gold  works  very  much  as  tin  does,  tin  instead  of  noncohesive  gold 
may  be  used  to  give  the  students  practice,  but  one  small  filling  of 
noncohesive  gold  should  be  inserted  to  impress  the  student  with 
the  points  of  difference. 

Exercise  10.  Tin  and  gold.  Ropes  or  ribbons  of  tin  and  gold 
are  prepared  by  placing  a  strip  of  tin  foil  upon  a  strip  of  non- 
cohesive gold  foil,  rolling  or  folding  it  with  the  tin  inside  of  the 
gold.  Cylinders  of  tin  and  gold  ribbons  may  be  made  in  the  same 
manner  as  cylinders  of  gold  or  tin  alone.  These  preparations  are 
inserted  in  the  same  manner  as  described  for  tin  in  cavities  which 
the  teacher  shall  select. 

Exercise  11.  A  cavity  of  division  A,  class  2,  Fig.  216  should 
be  filled  with  cohesive  gold,  beginning  with  semicohesive  gold  and 
finishing  with  extra  cohesive  gold.  The  gold  for  this  exercise 
should  be  short  pieces  cut  from  ribbons  made  of  leaves  of  No.  4 
foil  cut  into  four  strips.     All  gold  fillings   should   be  finished  with 


PRACTICAL  EXERCISES.  97 

fine  files  or  file  trimmers,  and   polished  with  fine   emery  strips  and 
rouged  chamois  skin  strips. 

In  these  exercises  all  cavities  should  be  inspected  and  their 
form  and  margins  passed  upon  by  the  teacher  before  the  student  is 
allowed  to  fill  them.  Each  filling  should  also  be  inspected  and 
passed  upon  before  the  student  is  allowed  to  proceed  with  the 
next  exercise. 

Specimen  Course  as  Used  by  the  Author. 

Tpxf-R     V       ^  Black's  Dental  Anatom}-. 

(  Weeks'  Manual  of  Operative  Technics. 

DENTAL    ANATOMY. 

f  Terminology  and  Nomenclature. 

1.  Descriptive  Anatomy     ;  Notation. 

of  the  Teeth.  ]  Form. 

[  Arrangement. 

i    Component  parts,  their 
Macroscopic  \    form,     proportion    and 

2.  Structural  Anatomy  J  (    relation  to  the  whole. 


of  the  Teeth. 


I 


,;,.  .  Structure  of   the   com- 

Microscopic    i 

'^        {    ponent  parts. 


Study  by  recitation  and  practical  exercises. 

PRACTICAL     EXERCISES. — DESCRIPTIVE    ANATOMY. 

In  the  Drawing  Books.  Make  outline  drawings  of  the 
principal  surfaces  of  the  teeth. 

Model  in  clay  one  tooth  of  each  class. 

Select  a  tooth  of  each  denomination  from  a  miscellaneous  lot 
and  arrange  them  upon  wax  for  future  use. 

structural     anatomy — MACROSCOPIC, 
LONGITUDINAL     SECTIONS. 

Select  and  mount  upon  blocks,  teeth  of  one  side  of  each 
maxilla.  File  the  teeth  thus  mounted  until  pulp  chambers  and 
canals  are  exposed,  broaching  canals  with  piano  wire  explorer  as 
the  filing  progresses. 

Make  prints  in  the  printing  book  of  every  aspect  of  six  teeth 
of  each  denomination,  superior  and  inferior. 

In  longitudinal  sections  of  :j-^  only  la.  and  m.  aspects  need 

be  shown,   but  in  b.  li.  m.  and  d.  aspects  should  be  shown. 

4-0-0- i-o 


98  PRACTICAL  EXERCISES 

TRANSVERSE     SECTIONS. 

Cut  sections  of  teeth  of  one  side,  upper  ana  lower,  as  in  Figs. 
9.  and  10  Manual  of  Technics,  showing  form  at  gingival  line,  mid- 
root,  and  apical  third.  Print  on  the  pages  ruled  for  the  purpose, 
as  in  Fig.  7,  Manual  of  Technics.  Exchange  sections  and  print 
in  this  way  six  pages. 

Duplicate  sheets  of  each  leaf  must  be  furnished  the  teacher. 

MICROSCOPIC. 

Cut  and  mount  one  longitudinal  and  one  transverse  section  of 
an  incisor.  Make  drawing  in  drawing  book  of  the  several  tissues 
as  shown  under  the  microscope. 

The  student  needs  for  these  exercises  : 

1  stick  Am.  Ex.  sealing  wax. 

1  half  round  file,  8  inch,  bastard  cut,  medium  coarse. 

1  bench  vise. 

1  alcohol  lamp. 

1  jewelers'  hack  saw  with  12  saw  blades. 

1  wax  spatula. 

1  excelsior  ink  pad. 

1  rubber  pad,  3  in.  x  6  in.  x  y^  in. 

1  book  for    printing,    open  at    end.      Leaves    ruled  as  in 
Figs.  6  and  "7,  Manual  of  Technics. 

1  drawing  book. 

Some  fine  canal  explorers. 

Some  fine  sandpaper,   0  and  00. 

1  toothbrush. 

1  yard  cotton  cloth. 

1  salt  mouth  bottle  with  cork. 

1  large  ointment  jar. 
To  insure  uniformity,  and  to  give  students  advantage  of  lowest 
prices,  these  materials  are  to  be  had  at  the  desk. 

The  teacher  provides  the  teeth  for  cutting,  and  the  blocks  for 
mounting  ;  also  paper  tablets  same  texture,  size  and  ruling  as 
books,  and  some  tablets  of  similar  paper  for  experimental  print- 
ing, and  clay  for  modeling. 

OPERATIVE    TECHNICS. 

T  T     ,  .  (  Classification  according  to  form  and  uses. 

I.        Instruments.  \  ^^^^^^  ^^  ^^^  j^^  ^^^^  ^^^^^ 


PRACTICAL  EXERCISES.  99 


[  Gaining  entrance  to  canal. 

II        Canal  J  ^^™°^^^  °^  P^^P- 

"\  Cleansing  and  preparing  canals. 

(  Filling  canals. 


Ill      Cavities. 


Classification  from  location  and  causes. 
Preparation  on  principles  governing. 


fconservative.         \  Treatment  and  protection. 
/  Capping. 

IV.  Pulp  Treatment.  < 

Radical  \  ^^^^^'^^]  devitalization 

l^  ■  I  Devitalization  by  drugs. 

i  Characteristics  and  composition. 

V.  Filling  Materials.       \  P^P^^^'.""'  .   , 

°  \  Introduction  into  cavities. 

'  Finishing  fillings. 

Study  by  recitation  from  Manual  of  Technics,  with  practical 
exercises. 

PRACTICAL    EXERCISES. 

Arrange  in  dummy  articulator  the  teeth  selected  from  miscel- 
laneous lot. 

Apply  rubber  dam  in  the  several  ways. 

Wrap  broaches. 

Gain  entrance  to  canals  in  one  incisor,  one  bicuspid  and  two 
molars,  removing  pulp  from  same. 

Cleanse  and  prepare  canal  for  filling. 

Fill  the  canals  thus  prepared. 

Prepare  cavities  as  in  Fig.  187,  Manual  of  Technics,  in  tooth- 
brush handle  or  celluloid  teeth. 

Prepare  cavities  of  each  division  of  the  several  classes,  in  teeth 
in  the  articulator. 

Treat  and  cap  two  or  more  exposed  pulps. 

Fill  the  cavities  in  toothbrush  handle  with  tin. 

Fill  the  other  cavities  prepared  : 

Two  or  more  with  gutta-percha. 
"  "         "     zinc  phosphate. 

"  "         "     amalgam. 

"  "         "     gold. 

All  remaining  cavities  are  given  proper  marginal  outlines  and 
the  contour  of  the  teeth  restored  with  oxyphosphate  or  gutta- 
percha. 

Instruments  for  this  work  as  per  list. 

Filling  materials  and  medicaments  furnished  at  the  desk. 

Recitations  every  session. 


100  PRACTICAL  EXERCISES. 

Written  quizzes  are  given  upon  completing  each  division  of  a 
topic  and  marked. 

Marks  are  given  on  the  cutting  of  sections,  silhouette  printing, 
drawings  and  operations. 

These  markings,  averaged  with  those  of  the  final  examination, 
determine  the  standing  of  the  student. 

The  examination  in  dental  anatomy  is  given  when  the  work  is 
completed.     That  in  operative  technics  at  the  close  of  the  term. 

In  the  last  half  of  the  second  semester,  those  students  who 
have  an  average  of  80  per  cent,  or  above,  in  their  practical  work, 
are  permitted  to  enter  the  infirmary,  to  put  in  practice  under  the 
direction  of  the  clinical  professor,  the  principles  which  have  been 
acquired  in  the  technic  laboratory. 

No  student  will  be  permitted  to  begin  practical  work  unless 
provided  with  the  instruments  and  other  necessaries  required  by 
the  college. 


GLOSSARY. 


Abrade.      To  rub  or  wear  away. 

Abrasion.  The  act  of  wearing  or  rubbing  off  by  friction  or 
attrition. 

Absorb.     To  drink  in;  imbibe,  as  a  sponge. 

Absorbent.     Capable  of  Imbibing,  taking  up  moisture. 

Adhere.      To  stick  fast,  one  thing  to  another. 

Adhesion.      The  act  of  adhering;  uniting  as  by  cement. 

Adhesive.     Sticky;  tenacious. 

Affinity.  Inherent  likeness  between  things.  In  chemistry, 
that  force  by  w^hich  the  atoms  of  dissimilar  bodies  unite  in  certain 
definite  proportions  to  form  a  new  compound. 

Alveolar,  Alveolus.  A  deep  cavity  or  socket.  Alveolar 
processes.  The  processes  of  the  maxillary  bones  containing  the 
sockets  of  the  teeth. 

Alloy.  An  artificial  compound  of  two  or  more  metals  com- 
bined while  in  a  state  of  fusion;  result,  a  new  metal. 

Amalgam.  A  compound  of  mercury  with  another  metal,  or 
an  alloy  in  which  the  combination  is  by  the  action  of  the  mercury. 

Amalgamated.     Mixed  or  united  with  mercury. 

Amorphous.      Without  form;  having  no  regular  structure. 

Anaesthesia.  Insensibility,  especially  to  pain.  General,  as 
applied  to  the  whole  body;  local,  as  applied  to  a  part. 

Anastomose.  To  communicate  or  unite;  inosculate,  or  run 
into  one  another. 

Angle.  The  difference  in  direction  of  two  intersecting  lines. 
The  figure  or  projection  formed  by  the  meeting  of  two  lines;  a 
corner. 

Anneal.  To  heat;  to  treat  by  heating  to  redness  and  gradual- 
ly cooling;  to  soften. 

Annealed.     Softened,  heated. 

Anodyne.  Having  power  to  remove  pain.  A  drug  which 
relieves  pain,  as  an  opiate  or  narcotic. 

Antiseptic      Anything  which  destroys  the  microorganisms  of 


102  GLOSSARY. 

disease,  'putrefaction,  or  fermentation,  or  which  restricts  their 
growth  and  multiplication. 

Apex.  The  tip  or  point  of  anything.  The  end  or  point  of 
the  root  of  a  tooth.      Plural,  apices. 

Apical.     Relating  to  the  apex. 

Apical  Foramina.  The  small  openings  in  the  apices  of  the 
roots  of  teeth,  which  give  passage  to  the  vessels  and  nerves  sup- 
plying the  pulp. 

Arch.  In  geometry,  any  part  of  the  circumference  of  a  circle. 
Dental  arch.  The  curved  line  of  the  teeth  in  their  sockets,  cor- 
responds to  the  alveolar  border  in  each  jaw. 

Articulator.  An  apparatus  for  obtaining  the  correct  articula- 
tion or  occlusion  of  artificial  teeth.  The  dummy  articulator  is  an 
apparatus  for  the  correct  arrangment  and  retention  of  natural  teeth 
for  operations  in  operative  technics. 

Asbestos.  A  fibrous  variety  of  horblende,  composed  of  sepa- 
rable filaments. 

Asbestos  Paper  or  Felt.  A  nonconducting  substance  made 
from  the  fibers  of  asbestos. 

Aseptic.  Free  from  the  living  germs  of  disease,  fermenta- 
tion, or  putrefaction. 

Asepsis.     Absence  of  the  living  germs  of  disease,  etc. 

Atom.  The  unit  of  matter.  The  smallest  mass  of  an  ele- 
ment that  exists  in  a  molecule. 

Atomic.      Pertaining  to  an  atom. 

Attrition.     The  act  of  wearing  away  by  rubbing  or  friction. 

Axial  Wall.  The  wall  which  is  parallel  with  a  longitudinal 
surface  and  opposed  to  it.  In  cavities,  that  wall  which  is  parallel 
with  an  axial  surface.  This  wall  has  formerly  been  variously 
designated  as  the  floor  or  base.  The  author  applies  the  term  base 
to  that  portion  of  cavities  which  is  at  right  angles  with  the  axis; 
as  basal  wall  of  a  proximate  cavity  (same  as  cervical  wall). 

Axis.  The  central  line  of  any  symmetrical  or  nearly  symmet- 
rical body. 

Bevel.  The  obliquity  or  inclination  of  a  particular  surface 
of  a  solid  body  to  another  surface  of  the  same  body.  Bevel  of 
blades,    the  angle  of  the  cutting  edge. 

Biscuspid.  Having  two  cusps.  The  teeth  in  either  jaw  which 
succeed  the  deciduous  molars. 


GLOSSARY.  103 

Blade.  The  cutting  part  of  a  knife  or  any  cutting  tool  or 
instrument. 

Broach.  A  spit;  a  stake  or  any  sharp  pointed  thing.  In  den- 
tistry a  slender^  pointed  instrument,  either  smooth  or  barbed,  for 
use  in  root  canals. 

Buccal.  Pertaining  to  the  cheeks,  or  sides  of  the  mouth. 
Applied  to  the  surfaces  of  the  teeth  which  are  presented  toward 
the  cheeks. 

Bur.  A  form  of  drill  or  reamer  with  a  circular  head,  having  a 
series  of  leaves  or  cutting  edges  around  its  circumference;  designed 
for  side  cutting. 

Burnisher.  An  instrument  of  hardened  steel  or  other  hard 
substance,  having  a  highly  polished  surface;  designed  for  smooth- 
ing, polishing  and  condensing  metallic  surfaces. 

Calcific      That  makes  or  is  converted  into  a  salt  of  lime. 

Calcification.      The  deposition  of  lime  salts  in  a  tissue. 

Calcined.  Treated  by  heat  for  the  purpose  of  driving  off  im- 
purities or  reducing  the  substance  to  a  friable  mass. 

Calculus.  A  general  term  for  inorganic  concretions  or 
deposits.  In  dentistry  that  substance  deposited  upon  the  teeth 
from  the  saliva  or  serum. 

Canal.  A  duct,  channel.  The  channel  in  the  center  of  the 
roots  of  teeth,  which  contains  the  elongated  portion  of  the  puip. 

Capping".  The  operation  for  the  covering  and  protection  of 
an  exposed  pulp  from  irritation  and  thermal  changes. 

Cavity.  A  hollow.  That  portion  of  a  tooth  destroyed  by 
caries. 

Cement.  A  composition  which  being  made  in  a  plastic  con- 
dition becomes  hard.  The  term  applied  to  the  several  compounds 
of  zinc  used  in  filling  teeth. 

Cement  substance.  The  intervening  substance  which  unites 
the  enamel  rods. 

Cementum.  The  cortical  substance  resembling  bone  which 
covers  the  roots  of  teeth. 

Cervical.  Pertaining  to  the  neck.  Applied  to  the  constricted 
part  of  a  tooth  where  the  enamel  joins  the  cementum. 

Chisel.  A  tool  consisting  of  a  handle,  shank  and  blade;  de- 
signed for  heavy  cutting. 

Clamps.  Instruments  for  holding  things  in  position  or  for 
holding  two  or  more  things  together  by  pressure. 


104  GLOSSARY. 

Cleavage.  The  act  of  splitting.  That  property  of  enamel 
which  permits  it  to  break  readily  in  one  direction. 

Coalescence.  The  act  of  uniting.  Organic  union  of  similar 
parts. 

Cohesive.      Having  the  property  of  sticking  together. 

Cohesion.  The  force  by  which  the  molecules  of  the  same 
material  are  held  or  bound  together. 

Columnar.  Having  a  generally  cylindrical  form,  with  greater 
length  than  thickness. 

Compatibility.  The  quality  of  being  harmonious,  not  antag- 
onistic or  injurious. 

Component.  Composing;  entering  into  the  composition  of 
anything. 

Concave.  Hollow.  Any  part  of  the  circumference  of  a  circle 
when  viewed  from  the  center. 

Concentric.  An  arrangement  of  parallel  circles  around  a  com- 
mon center. 

Condensation.  The  act  of  being  made  compact;  consoli- 
dation. 

Conducting.  Conveying;  carrying;  transmitting,  as  heat  or 
electricity. 

Conservative.  Power  or  tendency  to  preserve  from  injury  or 
loss.  Conservative  treatment  of  the  pulp  is  that  which  attempts 
to  save  its  life  or  vitality. 

Consistency.  Physical  constitution;  as  dense,  soft,  etc.,  as 
consistency  of  cream,  mortar,  etc. 

Contact.     A  touching  of  two  bodies. 

Contour.  The  outline  of  a  figure  or  bodj^;  contour  filling, 
one  which  restores  or  makes  form. 

Convex.  Rounded;  arched.  Any  portion  of  a  circle  as 
viewed  from  the  outside. 

Corrosion.  The  act  or  process  of  eating  or  gnawing 
away;  the  disintegration  of  a  surface,  especially  by  chemical  agents. 

Corrosive.     Any  agent  which  will  corrode,  as  an  acid. 

Decalcified.  Deprived  of  lime.  As  the  lime  salts  are  dis- 
solved out  in  the  process  of  decay  the  dentine  becomes  decalci- 
fied. 

Deciduous.  Living  or  existing  during  a  definite  period;  not 
permanent,  or  perennial. 


GLOSSARY.  105 

Decomposition.  The  act  or  process  of  separating  the  con- 
stituent elements  of  a  compound  substance;  the  process  of  reduc- 
ing an  organic  body  to  a  state  of  decay  or  putrefaction. 

Deliquesced.  Melted  or  dissolved.  To  become  liquid  by 
absorbing  moisture  from  the  air. 

Dentine.  The  principal  substance  composing  teeth.  It  is 
made  up  of  very  fine  close  set  tubules  or  canaliculi,  whose  general 
direction  is  at  right  angles  w^ith  the  pulp  chamber. 

Denuded.      Stripped  or  divested  of  covering;  laid  bare. 

Desiccated.     Thoroughly  dried,  deprived  of  a// moisture. 

Devitalized.  Deprived  of  life,  or  the  qualities  which  sustain 
life. 

Disk.  A  flat  or  approximately  flat  circular  plate  of  metal  or 
other  substance. 

Distal.  Away  from  or  opposite  the  median  line.  Applied  to 
the  surfaces  of  the  teeth  which  are  farthest  from  the  median  line 
following  the  dental  arch.     Same  as  posterior. 

Disto-lingual.  The  term  applied  to  the  angle  formed  by  the 
junction  of  the  distal  and  the  lingual  surface. 

DistO-marginal.  The  term  applied  to  the  angle  formed  by 
the  junction  of  a  distal  surface  and  a  margin. 

Dowel-pin.  A  pin  or  tenon  used  for  securing  together  two 
pieces  of  anything,  as  a  crown  to  a  root. 

Dovetailed.      Having  the  form  of  a  pigeon's  tail  spread. 

Drill.  An  instrument  for  boring  holes.  Specifically  an  instru- 
ment which  cuts  only  at  the  end. 

Ductility.  That  property  of  metals  which  renders  them 
capable  of  being  extended  by  drawing;  as  gold  into  wire. 

Edge-strength.  That  property  which  renders  an  extended 
edge  capable  of  resisting  strain. 

Electrolysis.  The  decomposition  of  a  chemical  compound 
into  its  constituent  parts  by  electricity. 

Elementary.      Primary;  simple;  uncompounded. 

Embryological.      Relating  to  the  subject  of  embryos. 

Enamel.  The  hardest  part  of  a  tooth;  it  is  composed  of  six- 
sided  prisms  or  columns  and  covers  the  crowns  of  teeth. 

Environment.  The  aggregate  of  surrounding  things  or  con- 
ditions. 

Escharotic  Caustic;  havmg  the  power  of  searing  or  destroy- 
ing the  flesh.  , 


106  GLOSSARY. 

Excavators.  Instruments  for  scooping  out  decay,  enlarging 
and  shaping  cavities. 

Excision.     The  act  of  cutting  off,  out  or  away. 

Explorers.  Instruments  for  searching  out  cavities  on  the  sur- 
faces of  the  teeth;  or  for  examining  and  following  cavities,  sinuses 
and  root  canals. 

Extractors.  Instruments  for  removing  or  withdrawing  pulp 
tissue  from  canals. 

Faces.  The  principal  surface  of  anything,  the  side  or  part  of 
an  instrument  upon  which  its  use  depends. 

Fibrillae.  The  delicate  threadlike  processes  of  the  outer 
layer  of  pulp  cells,  which  penetrate  the  dentine. 

Fissure.  A  cleft ;  a  crack.  Fissures  in  teeth  arise  from 
structural  imperfections  in  the  enamel. 

Foramina.  The  openings  in  the  apical  portion  of  the  roots 
of  teeth  which  give  passage  to  the  vessels  supplying  the  pulp. 

Force.     Active  power;  power  in  motion. 

Formative.  Having  the  power  to  give  form  or  shape.  Per- 
taining to  development. 

Fracture.  Separation  of  the  parts  of  a  solid  body  by  the  ac- 
tion of  force. 

Fusing".  Melting  ;  reducing  from  a  solid  to  a  fluid  state  by 
heat. 

Galvanic  Pertaining  to  galvanism;  current  electricity  pro- 
duced by  a  chemical  battery. 

Germicide.  A  substance  capable  of  killing  germs  or  micro- 
organisms. 

Gingival  line.  The  line  of  attachment  of  the  gums,  gingivae  ; 
the  line  of  junction  between  enamel  and  the  cementum. 

Gingival  Margin.  The  free  margin  of  the  gums;  the  mar- 
gin of  a  crown  surface  which  borders  on  the  gingival  line. 

Grade.  Relative  position  or  standing  as  regards  quantity, 
quality,  or  office. 

Groove.     A  long  shaped  depression  or  hollow. 

Gums.  The  soft  tissue  which  covers  the  alveolar  parts  of 
both  upper  and  lower  jaws,  enveloping  the  necks  of  the  teeth. 

Gutta-Percha.  The  concrete  juice  of  the  Isonandra  gutta- 
percha tree. 

Handle.  That  part  of  an  instrument  to  be  grasped  by  the 
hand  in  using  it. 


GLOSSARY.  107 

Histology.  The  science  of  minute  or  microscopical  anatom- 
ical structure. 

Homogeneity.     Of  uniform  structure. 

Homogenous.     Of  the  same  kind;  uniform. 

Hyperaemia.     Excessive   accumulation   of  blood  in  any  part. 

Incisal.      That  which  cuts  or  divides. 

Incisors.  Incisive  or  cutting  teeth.  The  two  teeth  on  each 
side  of  the  median  line  in  both  upper  and  lower  jaws. 

Inferior.     Situated  below  or  in  an  inferior  position. 

Inflammation.  A  morbid  condition  characterized  by  heat, 
pain,  redness  and  swelling,  generally  the  result  of  irritation  of  some 
kind. 

Ingot.     A  mass  of  metal  cast  in  a  mold. 

Inlays.     That  which  is  laid  into  or  inserted  in  a  surface. 

Integrity.      Unimpaired  condition;  soundness  of  state. 

Interdental.     Occurring  between  the  teeth. 

Interdigitation.  State  of  being  interwoven  or  run  into  each 
other. 

Intermediate.     Intervening;  interposing;  coming  between. 

Irritation.  The  act  of  evoking  some  action  or  change  of 
state. 

Labial-  Pertaining  to  the  lips.  Applied  to  the  surfaces  of 
the  teeth  presented  to  the  lips. 

Lancet.  A  small  surgical  instrument  for  cutting  soft  tissues, 
as  opening  abscesses,  etc. 

Ligatures.      That  which   serves  for  tying,  binding  or  uniting. 

Lingual.  The  term  applied  to  the  surfaces  of  the  teeth  next 
to  the  tongue,  both  upper  and  lower. 

Longitudinally.     In  the  direction  of  length. 

Lymphatic.      Pertaining  to  the  vessels  which    convey  lymph. 

Macroscopic      That  which  is  seen  by  unaided  vision. 

Malleable.      Capable  of  extension  by  hammering  or  rolling. 

Mallet.  A  hammer  like  instrument  for  driving  another  tool 
or  instrument. 

Manipulation.     Mana^jement  or  use  of  anything  by  the  hand. 

Margin.  Border;  as  incisal  border  or  margin  of  labial  sur- 
face; gingival  border  or  margin  of  the  gums. 

Mastication.  Act  of  chewing.  The  process  of  triturating 
the  food  with    the   teeth. 

Matrices.     Plural  of  matrix. 


108  GLOSSARY. 

Matrix.      A  mold  which  gives  form  to  material  forced  into  it. 

Matrix  Clamp.     An  instrument  for  holding  a  matrix  in  po- 
sition. 

Membrana    Eboris.     Term   applied    to    the    outer  layer  of 
cells  of  the  pulp. 

Mesial.      Being  in  the  middle.     Pertaining  to  the  middle  line. 
The  surface  presented  toward  the  median  line. 

Mesio-marginal.     Term  applied  to  the   angle  formed  by  the 
junction  of  a  mesial  surface  and  a  margin. 

Metallurgy.     Science  of  metals.      The  art  of  working  metals. 

Microscopic      That  which  cannot    be   seen  without  the  aid 
of  a  microscope. 

Molar.     Belonging  to  a  mill.       Term  applied  to  the  grinding 
teeth. 

Molecular.      Relating  to  molecules. 

Molecule.     The  smallest  mass  of  any  substance    capable  of 
existing  in  a  separate  form. 

Mortise.      A  hollow  or  recess  cut  in  any  material  to  receive  a 
tenon  or  inlay. 

Mucus.      A  viscid    fluid    secreted  by   the  mucous  membrane. 

Mucous  Membrane.     The  membrane  which  lines  all  cavities 
and  canals  in  the  body  which  communicate  with  the  air. 

Necrosis.      The  death  of  a  circumsrcibed  piece  of  tissue. 

Nodules.      A  small  mass  of   mineral  matter  having  a  rounded 
form. 

Nomenclature.      A  list  of  scientific  names  arranged  system- 
atically. 

Nonconducting.     Incapable  of  transmitting  any  force,  such  as 
heat,  or  electricity. 

Noncorrosive.      Incapable  of  being  acted  upon  by  corrosive 
agents. 

Oblong.     Elongated.      Having    greater    length  than  breadth. 

Obtund.     To  dull,  blunt,  or  deaden.     To  reduce  the  violent 
action  of. 

Obtundent.      An  agent  which  obtunds. 

Occlude.     To  shut  or  close  together. 

Occlusal.      A  term  applied   to  the  cutting  edges  or  grinding 
surfaces  of  the  teeth;  those  surfaces  which  occlude. 

Octahedron.     A  solid  bounded  by  eight  faces. 
Odontoblastic.     Pertaining  to  the  odontoblasts. 


GLOSSARY  109 

Odontoblasts.     The  cells    from  which  dentine  is  developed. 

Opaque.     Impervious  to  light.     Not  transparent. 

Oral.      Of  or  pertaining  to  the  mouth. 

Oval.  Having  shape  of  a  longitudinal  section  of  an  egg; 
elliptical. 

Oxidation.      The  act  of  combining  with  oxygen. 

Paraffine.  A  substance  obtained  by  the  dry  distillation  of 
wood,  peat,  bituminous  coal,  wax,  etc.  Is  tasteless,  inodorous  and 
resists  the  action  of  acids  and  alkalies. 

Pathology.     The  science  of  diseased  conditions. 

Pericemental  The  term  applied  to  the  membrane  investing 
the  root. 

Periphery.     The  outside  or  superficial  part  of  a  body. 

Photo-micrographs.  Enlarged  or  microscopic  photographs 
of  microscopic  objects. 

Pit.  A  hollow  or  small  depression.  A  round  imperfection  in 
the  surface  of  the  enamel. 

Plastic.     Capable  of  being  moulded  into  new  forms. 

Plasticity.     Capability  of  being  moulded. 

Pliers.  Small  pincers  with  long  jaws  capable  of  handling 
small  objects. 

Pluggers.  Instruments  for  driving  or  packing  filling  material 
into  cavities. 

"Potential  cauterants."  Possible,  as  opposed  to  actual 
cauterants. 

Precipitation.  The  process  by  which  any  substance  is  made 
to  separate  from  others  in  solution,  and  fall  to  the  bottom. 

Prophylactic     Preventive,  defending  from  disease. 

Protoplasm.  A  nitrogenous  substance  from  which  nuclei 
are  formed. 

Proximate.  Next ;  immediate  ;  without  the  intervention  of 
a  third. 

Pulp.  The  formative  organ  of  the  tooth  consisting  of  connec- 
tive tissue,  nerves,  and  blood  vessels. 

Pulp  Chamber.  The  chamber  in  the  crown  of  a  tooth  which 
contains  the  bulbous  portion  of  the  pulp. 

Pus.  The  cream  like  fluid  found  on  the  surfaces  of  abscesses 
or  sores.     Matter. 

Putrescent  pulp.  A  pulp  which  has  become  disorganized  ; 
decomposed. 


110  GLOSSARY. 

Radical.  Pertaining  to  the  root.  Thorough.  Applied  in 
dentistry  to  mean  the  extirpation  and  removal  of  the  pulp. 

Reamer.  An  instrument  for  enlarging  holes.  A  side-cutting 
instrument. 

Regular  system.  Isometric,  or  having  three  equal  axes  at 
right  angles  with  each  other. 

Rhombic  A  solid  bounded  by  six  equal  and  similar  rhombic 
planes.     Diamond  shaped. 

Rhombic  System.     Crystallizing  into  rhombic  form. 

Ridge.  A  prominent  border.  An  elevated  line  or  crest  on 
the  surface  of  a  tooth. 

Root.  That  part  which  is  fixed  in  the  alveolar  socket,  and 
supports  the  tooth. 

Rubber  dam.     A  thin  sheet  of  flexible  soft  rubber. 

Scaler.  An  instrument  used  for  removing  deposits  from  the 
teeth. 

Semicohesive.  Having  cohesive  property  partially  de- 
stroyed. 

Semidecalcified.     Partly  decalcified. 

Sensitive.  Having  sense  or  feeling.  Capability  of  receiving 
impressions  from  external  objects.  Applied  to  a  tooth  means  in- 
crease or  perversion  of  normal  sensitiveness. 

Separators.  An  instrument  for  forcing  teeth  apart  to  gain 
space  between  them. 

Septic  Applied  to  condition  resulting  from  decomposition 
putrefaction,  or  fermentation. 

Serrations.  Notches  which  give  points  or  teeth,  like  the 
notches  of  a  saw. 

Socket.      An  opening  or  cavity  in  which  anything  is  fitted. 

Solution.      Preparation  made  by  dissolving  a  solid  in  a  liquid. 

Spatula.  An  instrument  having  flat  blade  with  unsharpened 
edges. 

Spherical.      Having  the  form  of  a  globe  or  ball. 

Spheroidal.  In  crystallization,  globose;  bounded  by  convex 
faces. 

Stability.  State  of  resisting  change.  Permanency.  Contin- 
uing in  same  state  or  condition. 

Sterilized.     To  render  free  from  living  germs. 

Stratum  granulosum.  Applied  by  some  authorities  to  the 
dividing  line  between  the  enamel  and  the  dentine. 


GLOSSAKY  111 

Sulcus,  pi.  Sulci-  A  more  or  less  linear  and  shallow  depres- 
sion. 

Syringe.  An  instrument  capable  of  drawing  in  fluid  and 
ejecting  it  forcibly. 

Tarnish.  To  diminish  or  destroy  the  luster  of.  A  slight 
change  in  surface  occasioned  by  contact  with  air  or  liquid. 

Technic  That  which  relates  to  the  practical  part.  The  per- 
formance, the  manipulation. 

Tenacity.  Toughness.  Having  great  cohesive  force  between 
its  particles. 

Terminal.  The  end,  limit.  The  extreme  end  or  boundary 
of  any  organ. 

Therapeutics.  The  composition,  application  and  mode  of 
operation  of  remedies. 

Thermal.      Pertaining  to  heat. 

Tissue.  An  aggregate  of  similar  cells  and  cell  products  in  a 
definite  fabric. 

Tortuous.     Winding.      Full  of  twists  or  turns.     Crooked. 

Traction.      State  of  being  drawn. 

Triturated.      Rubbed  or  ground  to  a  powder  or  pulp. 

Tubuii.      Plural  of  tubulus;  a  tube,  duct,  canal. 

Wedg"e.  An  acute  angled,  triangular  prism  driven  between 
objects  to  be  separated.     Ex.,  an  ax. 

Welded.      United  or  consolidated. 


INDEX. 

Absorbents,  cotton,  spunk  and  bibulous  paper 39 

Adjuncts 37 

Alloy,  characteristics  of  metals  for 78 

defined 77 

Aluminum,  characteristics  of 80 

influence  in  alloys 81 

Amalgam,  advantages  and  objections 81 ,  82 

chemical  and  electrical  changes 82 

color 82 

compatibility  with  tooth  substance 82 

conductivity 83 

copper .    81 

copper,  use  of 83 

defined 7(5 

density  and  hardness 81 

ease  of  introduction 81 

finishing 83 

inserting. 83 

instruments 31 

introduction  into  cavities 83 

lack  of  ductility  and  tenacity 82 

mixing 83 

molecular  change 82 

practical  exercises 94 

testing 94 

Angle  between  blade  and  shank,  purpose  of 20 

in  pluggers,  purpose  of 33 

scaler,  purpose  of 23 

Annealing  of  gold 88 

Antimony,  characteristics  of 78,  79 

influence  in  alloy 78,  79,  80 

Application  of  drugs  for  devitalizing 73,  74 

Applying  rubber  dam 39,  44 

Arrangement  of  teeth 6 

Arrested  development  in  relation  to  decay 53 

Arsenious  acid  for  devitalizing  pulp 73,  74 

Asbestos  for  pulp  capping  and  protection 69,  70 

Automatic  mallets 37 

Auxiliary  dovetail 62,  63 

Barb  broaches 3.") 

Black,  G.  v.,  course,  foundation  for  all  operative  technic  courses 2 


114  INDEX. 

Black's  one-two-three 50 

pioneer  course  in  operative  technics 2 

proposed  course 2 

Blade,  defined 17 

angle  between  blade  and  shank 20 

bevel 17 

finding  angle  of 17 

Blocks,  fastening  teeth  on 10 

marking  of 9 

Broaches,  barbed 35 

smooth 35 

Swiss 35 

use  of 50 

wrapping  with   cotton 50 

Burnishers 85 

Burs,  action  of 26 

finishing 26 

Canal,  cleansing 49,  50 

cleansing,  instruments  for 50,  51 

drying 48,  50,  51 

enlarging  opening  to,  with  burs 47 

explorers 35 

exploring  while  cutting  sections 10 

fillingof 48,  51 

gaining  entrance   to 44 

instruments 35 

instruments  for  removal  of  pulp 47,  48 

parafifine  for  filling 52 

point  of  opening ."^ 44 

removal  of  putrescent  contents 49  ' 

reaming  of ". 47,  50,  51 

rendering  aseptic 50 

rendering  contents  inert 49 

requisites  for  filling  material , 48 

shape  of  opening 44,  45 

treatment,   syllabus 43 

with  putrescent  pulp 49 

Capping  pulp 69 

materials  for 09,  70 

practical  exercises 70 

Carbolic  acid  for  devitalizing  pulp.  ...    73 

Carborundum  disks  and  points 29 

Cattell,  D.  M.,  outline  of  course 3 

Cavities,  class  1,  division  A,  rules  for  outline ....  58 

class  1,  division  A 56 

class   1,  division  B 59 

classification,    diagrammatic 53,  54 

classification  and  preparation   of , 53 


INDEX.  115 

Cavities,  classification,  reasons  for 53 

class  1,  rules  for  outline 59 

class  2 59 

class  3 62,   63 

explorers 35 

fillings  as  inlays 54 

filling  of,   general  consideration 75,  70 

formation  of,  for  tin 85 

in  which  tin  may  be  employed. .  .    85 

outline 61 

outline,  class  2 59 

pit  and  fissure 5G,   58 

predisposing  cause 53 

preparation  of,  class  3 63 

preparation  of,  practical  exercises 63,   66 

preparation  of,   for  gold 03,   66 

preparation  of,   for  plastics 63,   66 

preparation  of,  for  tin 64,   66 

Cavity  form,  rules  for,  class  1  and  2 . .    59 

Cement,  instruments  for 31 

Chemical  and  electrical  changes  in  amalgam 82 

Chisels,  manner  of  holding 46 

relation  of  blade  to  handle 20 

shaping 16,   20 

Chloro-percha 92 

for  canals 49,  52 

for  pulp  protection  and  capping 69,  70 

Chloride  of  zinc  for  devitalizing  pulp , 73 

Clamp,    matrix 35 

rubber  dam 35 

Classification  of  cavities,  diagrammatic 53,   54 

and  preparation  of  cavities 53 

and  preparation  of  cavities,  reasons  for 53 

Cloth  strips  for  finishing 29 

Cohesion  of  gold 87,  88 

Cohesive  gold 87,   88 

Color  of  amalgam 82 

Compatibility  of  amalgam  with  tooth  substance 83 

Condensing  instruments 31 

Conductivity  of  amalgam 82 

of  tin 84 

Conservative  pulp  treatment 07,  09 

Contour  for  contact 93 

for  form 98 

Copper  amalgam 81 

amalgam,   use  of 83 

characteristics  of 77,  78,   79 

influence  iw  alloys .78,  79,  80 


116  INDEX. 

Corundum,   defined 29 

disks  and  points 29 

and  hard  rubber  disks  and  points   29 

Cotton  absorbent 39 

Curve  between  blade  and  shank 20 

in  plugger,  use  of 33 

in  scaler,  use  of 23 

Decay,  predisposing  cause 53 

Dentine,  removal  of  decayed 47 

removal  of  decayed,  instruments  for 47 

Density  and  hardness  of  amalgam 81 

Dentinal  pyramid 55 

class  1  and  2 58,  59 

Development,  arrested,  relating  to  decay 53 

Devitalization  of  pulp,  by  arsenic 73,  74 

by  carbolic  acid 73 

by  chloride  of  zinc 73 

by  drugs 73 

surgical 71,  72 

practical  exercises 74 

Dickinson's  material 90 

Disks,  Arkansas,  Scotch,   Hindostan 29 

celluloid 29 

copper  and  diamond  dust,  emery  paper 29 

corundum 29 

cuttle  fish 29 

felt  29 

garnet 29 

paper,  grades  and  forms  of 29 

sandpaper , 29 

soft  rubber 29 

Dovetail,   auxiliary 62,  68 

Drawing  microscopic  sections  of  teeth 14 

outline  of  sections 14 

surface  of  teeth 6 

Dressing  pliers,  noncorrosive 41 

Drills,  action  of 26 

for  root  canals 26 

Drugs,  devitalization  of  pulp  by 73 

Drying  canals 48,  50,  51 

Ductility  of  amalgam 82 

tin 84 

Dummy  articulator 6 

Ease  of  introducing  amalgam 83 

Electro-magnetic  mallets 37 

Electrolysis,  removal  of  pulp  by 72 

Enamel,  bevel  for  protection  of 55,  56 

form  and  thickness  of 8,  14 


INDEX.  117 

Enamel  in  relation  to  mortise •  55 

pyramid 55 

pyramid,  class  1  and  2 59 

Enlarging  canal 47 

Excavators,  convex  edge,  purpose  of   23 

curved 23 

hatchet 28 

hoe 23 

primary  form 23 

rights  and  lefts  for  lateral  cutting 23 

shaping 16 

single  instrument 23 


spoon  or  scoop. . 


23 


square  pointed,  purpose  of 23 

Excluding  moisture,  how  accomplished 39 

Explorers,  canal 35 

cavity 35 

Files,    finishing 26 

flexo 26 

flexo   finishing. 26 

flexo  for  saw  frames 29 

handles  of 36 

separating 26 

trimmers 2(3 

Filling  canals , 48,  51 

cavities,  general  consideration 75,  76 

material,  general  consideration 76 

material  for  canals 48 

material,  requisites  for 76 

material  solidity,  how  attained 31 

material  gold 86,   87,  88 

Filling  teeth,  practical  exercises 92 

with  ropes  or  ribbons  of  tin 86 

with  tin  cylinders 85 

Fillings  in  clay  models 92 

Finishing  amalgam 83,  9.') 

gold 97 

gutta-percha 94 

oxychloride  of  zinc 94 

oxyphosphate  of  zinc , 94 

tin 96 

Foil  carriers 39 

gold   8!l 

gold,  preparation  for  inroduction 89 

tin 84 

Force,  laws    of  delivery 32 

Form,  study  of 6 

Function  of  pulp 67,  68 


118  INDEX. 

Gaining  space 37 

Gold,  advantages  of  as  a  filling  material 87,   88,  89 

annealing  of 88 

and   tin 89 

as  a  filling  material 86,  87 

characteristics  of 87,   88,  89 

cohesion  of , 88 

cohesive,  how  introduced 31,  89 

cohesive,  instruments   for 31,  89 

cohesive,   instruments  for    introducing 31,  89 

finishing 97 

foil 89 

preparation  of,  for  insertion 89 

influence  in  alloys 78,   79,  80 

insertion  of 88 

noncohesive 88,  89 

noncohesive,    advantages  of 89 

noncohesive,  how    introduced 31,  89 

noncohesive,  instruments   for 31,  88,  89 

noncohesive,    introduction    of 88 

noncohesive,  practical    exercises 95,  96 

preparation  of 87 

semicohesive 87 

soft 87 

Grinding  instruments 28 

Gutta-percha   instruments 31 

characteristics  of 91 

finishing.  . 94 

for  canals 47,  50 

for  pulp  protection  and  capping ^ 69,  70 

high   heat 92 

insertion 92 

low  heat 93 

manipulation    of ....  92 

medium 92- 

pink  base  plate 92 

practical  exercises 92 

Hand  mallets 37 

Handle  for  file 26 

for   instruments 20 

for  lancet 23 

socket 20 

Inlays — fillings 54 

mortise  for 54 

Insertion  of  amalgam. 83 

gold 88 

gutta-percha , 92 

oxychloride  of  zinc 94 


INDEX.  119 

Insertion  of  oxyphosphate  of  zinc 94 

tin 95 

Instruments,   amalgam BI 

blades  of 17 

canal i}5 

classification  of ; 18 

description  of •. 17 

enamel,  bevel  of  blade 20 

enlarged 92 

for  filling 81 

for  finishing  fillings 26 

for  gutta-percha 31 

for  introducing  tin 85 

for  removal  of   pulp 47,  51 

for  tin  and  noncohesive  gold   31 

for  tin 95 

for  uforking  plastics 31 

grinding 29 

hardening 17 

noncorrosive 31 

polishing 10 

sharpening 17 

tempering 17 

Introductory 1 

Knowledge,  two  kinds 1 

Lancets,  description  of 23 

Lancet  trimmers 29 

Ligatures 39 

Making  cylinders 95 

ropes  or  ribbons 95 

Mallets,  automatic 37 

electro  magnetic 37 

hand    37 

mechanical 37 

pneumatic 37 

Manual  training,  underlying  principles 1 

Materials  for  filling  cavity,  general  consideration    75 

requisites  for 76 

tin 84 

Material  for  wedging 39 

Matrices,  application  of 37 

purpose  of 37 

Matrix  clamps 35 

Mechanical  mallets 37 

separators 37 

Mercury,  characteristics  of 77,  78 

influence  upon  metals 77,  78,  79 

Metal  disks  in  pulp  capping 71 


120  •  INDEX. 

Metals  for  amalgam  alloys 77 

Mirrors,  mouth 39 

Mixing  amalgam 83 

oxychloride  of  zinc 94 

oxyphosphate  of  zinc 94 

Modelling  teeth 6 

Molecular  change,  freedom  from  in  tin 85 

in  amalgam 82 

Mortise,  dovetailed 54 

grooved 54 

plane 54 

rounded 54 

various  forms 54 

Mouth  mirrors 39 

Nomenclature   5 

Noncohesive  gold 88 

advantages  of , 89 

instruments  for  introducing , 89 

introduction  of 88 

Opening  of  cavity,  instruments  for   46 

Operative  technics,  governing  principles 1 

Outline  of  course 5 

Oxychloride  of  zinc 90 

finishing  of 94 

for  canals 49 

for  pulp  protection  and  capping 69,   70 

insertion  of 94 

mixing  of 94 

practical  exercises 94 

Oxyphosphate  of  zinc ^ 90 

finishing  of 94 

for  canals , 49 

for  pulp  protection  and  capping 69,  70 

insertion  of 94 

mixing  of 94 

practical  exercises 94 

with  gelatinized  fluid 91 

Painless  removal  of  pulp 72 

Palladium,  characteristics  of 77 

influence  in  alloys 78,   79,   80 

Paper,  bibulous,  absorbent 39 

strips  for  finishing 29 

Paraffine  for  canals 52 

Plastics 90 

zinc 90 

Platinum,   characteristics  of 77 

influence  in  alloys 78,  79,  80 

Pliers,  dressing .  ...    39 


INDEX.  121 

Pluggers,  ball  end 33 

enla'-ged 92 

forces  of - 33 

purpose  of 31 

triangular  foot,  with    matrix    fillings 83 

Pneumatic  mallets 37 

Points,  for   grinding  and    finishing 39 

gutta-percha  and  metal,  for  canals 51 

leather 29 

plugger 31 

soft  rubber 29 

wood 29 

Polishing  powders 29 

Portes  for  strips 29 

Practical  exercises  for  devitalizing  pulp 74 

in   amalgam 94 

in  gold 96 

in  gutta-percha , 93 

in    oxychloride   of    zinc 94 

in  oxyphosphate  of  zinc 94 

in  tin 95 

in  tin  and  gold 96 

Predisposing  causes  of  decay 53 

Preparation  of   cavities,  class  1 55,  56,  58,  59 

class  2 59,  61,  62 

class  3 63,  64 

for  gold 64 

for  plastics 04,  66 

for  tin 64 

for   practical  exercises 64,  66 

Preparation  of  tin  for  cavities 84 

Protection  of   the  pulp 69 

materials  for 69 

practical  exercises 70 

Pulp  capping .  .    69 

materials  for 70 

Palp  chamber  and  canal 7 

Pulp,  function  of .  07,  68 

painless  removal  of 72 

protection   69 

protection  and  capping,  practical  exercises   70 

protection,  materials  for 69 

removal  of 47 

study  of  form  and  location 14,  67,  68 

treatment,  general  consideration 67 

treatment,  conservative  and  radical 67 

treatment,   radical 71 

Putty 92 


122  INDEX. 

Putrescent  pulp 49 

Pyramid,  dentinal 55 

enamel 55 

enamel  and  dentinal,  class  1  and  2 59 

Pyrozone 49 

Reamer,  actions  of 26 

for  root  canals 2G 

Reaming  canal 47,  5U,  51 

Relief  line,  advantages  of . ! 8 

Removal  of  decayed  dentine 47 

of  pulp 47 

of  pulp  by  electrolysis 72 

Requisites  for  students 9 

provided  by   teacher , .     9 

Rubber  dam 39 

application  of ; 39 

applying  clamp 44 

applying  with  ligatures 44 

application  without  ligatures 44 

clamps 35 

Rubber  clamps,  application  of 44 

hard  and  corundum 29 

tooth  forms 92 

tooth  forms,  advantages  of 93 

Saws,  frames 29 

separating 29 

Scalers,  angles  and  curves  in 23 

purpose  of 23 

blade  of '.  . .   23 

description  of , 23 

for  deep-seated  calculus 23 

for   heavy    deposits 23 

shaping 16 

Sections,    cutting .' 8 

cutting  longitudinally 7 

cutting  microscopic 14 

duplicate    sheets   of 8 

filing  in  trays 8 

longitudinal  aspect  shown 11 

prints  of 8 

mounting  and  annotating 9,   10 

transverse 13 

transverse,  value  of 12 

Semicohesive  gold   87 

Separating  teeth,  how  accomplished 37 

Separators,    mechanical 37 

Serrations 32 

Shank,  purpose  of 23 


INDEX.  123 

Shavings  of  tin o4: 

Silhouettes,  printing 10 

sample  page,  longitudinal -il 

transverse 1-^ 

transverse  sections,  sample  page 13 

Silk  ligatures 39 

Silver,    characteristics  of ^^ 

influence  in  alloys 78,  79,  80 

Smooth  broaches 35 

Soft  gold 87 

Spatulas,  forms  and  uses  of 31 

Specimen  course 97 

Spunk 39 

Steel,  annealing Ki 

defined 15 

filing '. 16 

hardening  of 1  < 

and  instruments 15 

melting  point  of I'J 

practical  exercises 10 

softening   of 15 

specific  gravity 15 

temper   of 15 

temper  indicated  by  color 16 

Strips,  cloth  and  paper  for  finishing 29 

Structural   anatomy 7 

anatomy,  microscopic 14 

imperfections. .    53 

Surgical  devitalization 71 

S  wiss  broaches ,    35 

Teacher,  duties  of ■'^ 

outlining  enamel 8 

Technic  laboratory  equipment 5 

Tenacity  in  amalgam 83 

Terminology 5 

Testing  amalgam 94 

Tin  and  gold 89 

practical  exercises 96 

Tin  as  a  filling  material 84 

capability  of  polish 85 

cavities  where  employed 84,  85 

characteristics  of 77 

conductivity  of 84 

density  and  hardness 84 

ease  of  introduction 84 

filling  with  ropes  or  ribbons 8() 

finishing 96 

foil 84 


134  INDEX. 

Tin,  formation  of  cavities  for 85 

freedom  from  chemical  action 84 

freedom  from  molecular  change 85 

influence  in  alloys 78,  79,  80 

insertion   of 95 

instruments  for 31 

introduction  of  cylinder  fillings 85 

making  cylinders  of 95 

making  ropes  or  ribbons 95 

practical  exercises 95 

preparation  for  introduction  into  cavities.      84 

tenacity  of 84 

Treatment,  pulp,  radical 71 

Trimmers,  file ....  2G 

lancet 29 

Using  broaches 50 

Wedging  materials 39 

Wheels,   corundum 29 

grinding 29 

Wrapping  broaches 50 

Zinc,  characteristics  of 77 

influence  in  alloys 78,   79,  80 

oxychloride  of 90 

oxyphosphate  of 90 

oxyphosphate  with  gelatinized  fluid 91 

plastics 90 


There 

Are  several 

Kinds  of 

Porcelain  Teeth. 

But  none 

Are  so 

Well  adapted 

For  the  dentist 

And 

His  patients 

As  those 

Produced  by 

H.  D.  Jus n  &  Son, 

f->hil-ade:lphia.  ohioago. 


They  excel  all 

Others 

In  quality 

And  utility. 

They 

Are  very  cheap 

In  price,  and 

Supplied 

By  dental  dealers 

Throughout 

The 

World. 

H.  D.  JusTi  &  Son, 

PHI1_ADE1_PHIA.  CHICAGO 


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